Skip to main content
ExamExplained
NSW · Modern History
Modern History study scene
§-Syllabus dot point
NSWModern HistorySyllabus dot point

How was the war conducted by the United States and its allies from 1965 to 1968?

The nature and conduct of the war from 1965 to 1968, including the strategies of attrition and search and destroy, the use of air power and Operation Rolling Thunder, the role of Australia and other allies, and the experience of combatants and civilians

A focused answer to the HSC Modern History Indochina dot point on the conduct of the war. Westmoreland's attrition and search and destroy, the body count, Operation Rolling Thunder, the use of helicopters, napalm and Agent Orange, the role of Australia at Long Tan and Phuoc Tuy, the experience of US conscripts and Vietnamese civilians.

Reviewed by: AI editorial process; not yet individually human-reviewed

Have a quick question? Jump to the Q&A page

Jump to a section
  1. What this dot point is asking
  2. The answer
  3. In one sentence
  4. Examples in context
  5. Try this

What this dot point is asking

NESA expects you to describe the conduct of the war from US escalation to Tet. Strong answers cover Westmoreland's strategy of attrition and search and destroy, the air war over the north, the role of allies (especially Australia in Phuoc Tuy), the technology of helicopter mobility and chemical defoliation, and the human experience on both sides.

The answer

The US strategy

General William Westmoreland, MACV commander from June 1964, adopted attrition. The goal was to inflict casualties on PAVN (the People's Army of Vietnam, also known as NVA) and PLAF until the "crossover point" at which losses exceeded replacements. The body count was the metric; battles were rated by kill ratios. The strategy assumed a conventional, Korean-style war.

Search and destroy operations sent battalion- and brigade-strength forces by helicopter into enemy base areas. Operations Cedar Falls (8 to 26 January 1967, Iron Triangle, around 30,000 US troops) and Junction City (22 February to 14 May 1967, War Zone C, around 35,000 US troops) were the largest. PAVN units typically withdrew across the Cambodian border into the Fishhook and Parrot's Beak; the operations returned strategic ground to the enemy.

Pacification, the political-civic side, was handled by CORDS (Civil Operations and Revolutionary Development Support) from May 1967 under Robert Komer. CORDS achieved limited rural improvements; from 1968 the Phoenix Program targeted the NLF infrastructure (around 26,000 killed by 1972).

Operation Rolling Thunder

Rolling Thunder ran from 2 March 1965 to 1 November 1968. The campaign delivered around 864,000 tonnes of bombs on the north (more than US bomb tonnage on Germany in the Second World War). Targets were graduated, controlled from Washington Tuesday lunch meetings; major targets in Hanoi and Haiphong, the dyke system, and the Sino-Vietnamese border buffer were off-limits for much of the war.

The campaign failed to halt the flow of supplies south. The POL campaign of mid-1966 destroyed around 70 per cent of north Vietnamese oil storage; PRC and Soviet imports compensated. The MiG-21s and SAM-2s introduced from 1966 imposed serious losses (around 990 US fixed-wing aircraft lost to all causes over the north, 1965 to 1968). Around 30,000 north Vietnamese civilians were killed by the bombing.

Helicopters, chemicals, and the war on the ground

The Bell UH-1 Iroquois ("Huey") provided air mobility on a scale never before seen. The 1st Cavalry Division (airmobile) deployed in 1965; the Ia Drang campaign of October to November 1965 was the first major air-mobile battle. Around 12,000 US helicopters operated in country; around 5,000 were lost.

Operation Ranch Hand (1962 to 1971) sprayed around 20 million gallons of defoliants, including around 11 million gallons of Agent Orange (dioxin-contaminated 2,4,5-T and 2,4-D). Around 12 per cent of South Vietnam, including 50 per cent of Mekong Delta mangrove, was defoliated. Long-term health effects on Vietnamese civilians, US veterans, and Australian veterans included birth defects and cancers; class-action settlements followed in the 1980s.

Napalm and white phosphorus were used extensively in close air support. Free fire zones declared whole areas hostile and authorised unrestricted fire. Around five million southerners were displaced; rural Vietnam emptied into city slums.

The role of Australia and other allies

Australia entered the war on 29 April 1965 under the Menzies government, citing the SEATO treaty. The Royal Australian Regiment served in Bien Hoa from 1965; from June 1966 the 1st Australian Task Force (1ATF) operated from Nui Dat in Phuoc Tuy Province. Peak strength was around 8,500 personnel.

The Battle of Long Tan on 18 August 1966 saw D Company 6RAR (108 men) hold off a regimental-strength PAVN/PLAF assault in a rubber plantation. 18 Australians and around 245 PAVN/PLAF were killed. Australian doctrine emphasised foot patrolling, ambush, and engagement with the local population; Phuoc Tuy was held relatively secure throughout the deployment.

Around 60,000 Australians served. 521 died; around 3,000 were wounded. Conscription via the National Service Act (24 November 1964) was a major domestic political issue; the Moratorium marches of 1970 and 1971 mobilised an estimated 200,000 in Melbourne.

Other allies: South Korea (peak around 50,000 troops, including Tiger Division and Capital Division, brutal counter-insurgency reputation, around 5,000 killed); Thailand (around 11,000); the Philippines (around 2,000 civic action); New Zealand (around 550, attached to 1ATF). South Vietnam mobilised the ARVN to around 1.1 million by 1968 with mixed quality.

The experience of combatants

US ground troops were 25 per cent draftees overall but 88 per cent of infantry by 1969. The one-year tour rotation produced units with constantly changing personnel; the 13-month tour of officers was shorter still. Around 2.7 million Americans served. 58,220 died; around 304,000 were wounded. Combat fatigue, drug abuse, and "fragging" (attacks on officers) escalated towards the end. African Americans were over-represented in combat infantry and casualties (around 12.5 per cent of the population, around 14.1 per cent of fatalities to 1969).

PAVN/PLAF combatants endured the Trail, US bombing, and chronic supply shortages. Total Vietnamese military deaths (north and south combined, including NLF and ARVN) exceeded 1.1 million.

The civilian experience

Around two million Vietnamese civilians died across the war. The My Lai massacre, 16 March 1968, saw Charlie Company, 1st Battalion 20th Infantry, kill around 504 unarmed villagers in Son My village in Quang Ngai. The cover-up unravelled in 1969 (Seymour Hersh's reporting). Only Lt William Calley was convicted (29 March 1971, life imprisonment, paroled 1974).

The war emptied the countryside. Saigon's population grew from around 1.4 million in 1954 to around 4 million by 1975. Refugees, prostitution, and a black-market economy reshaped urban life.

US strategy 1965 to 1968 and why it failed

US strategy in Indochina, 1965 to 1968, and why it failed A concept map: three pillars of US strategy - attrition with search and destroy and the body count on the ground, Operation Rolling Thunder in the air, and escalation to around 536,000 troops - all aimed at breaking Hanoi's will, with a band below each pillar explaining why it failed: Hanoi absorbed losses and sanctuaries let PAVN refit; gradualism and resupply blunted the bombing; and firepower alienated the rural population. US strategy 1965 to 1968 and why it failed Attrition search and destroy, the body count Rolling Thunder around 864,000 tonnes on the north Escalation to around 536,000 troops by 1968 Goal: break Hanoi's will to fight Why each pillar failed Attrition Hanoi absorbed losses; sanctuaries in Cambodia and Laos let PAVN refit Rolling Thunder Gradualism, off-limits targets and PRC/Soviet imports blunted it Firepower war Free fire zones and defoliation alienated the rural population Result: military dominance, political defeat by Tet 1968 My Lai (16 March 1968); Johnson withdraws 31 March 1968

Conduct of the war, 1965 to 1968 A vertical timeline from March 1965 to March 1968: Operation Rolling Thunder begins and US ground troops land, Australia commits combat troops, the Battle of Long Tan, the 1967 search and destroy operations Cedar Falls and Junction City, US strength peaks around 536,000, the My Lai massacre, the Tet Offensive, and Johnson's 31 March 1968 withdrawal and bombing halt. Escalation to Tet, 1965 to 1968 Mar 1965 Rolling Thunder; US ground troops land 29 Apr 1965 Australia commits combat troops 18 Aug 1966 Battle of Long Tan, Phuoc Tuy Jan to May 1967 Cedar Falls and Junction City 1967 to 1968 US strength peaks around 536,000 Jan to Mar 1968 Tet Offensive shatters US confidence 16 Mar 1968 My Lai massacre, Son My 31 Mar 1968 Johnson halts bombing, withdraws

Historiography

Andrew Krepinevich (The Army and Vietnam, 1986) argues the conventional Army misapplied a big-unit doctrine to a counter-insurgency war.

Lewis Sorley (A Better War, 1999) argues Creighton Abrams from 1968 onwards adopted a winning pacification approach and the war was lost politically at home.

Christian Appy (Working-Class War, 1993) on the class composition of the US infantry.

Heather Marie Stur on Australian and US gender, race, and rear-echelon dynamics.

In one sentence

US strategy in Indochina from 1965 to 1968 combined attrition and search and destroy on the ground, Operation Rolling Thunder in the air, and pacification through CORDS, with allies including Australia (Phuoc Tuy, Long Tan 18 August 1966) and South Korea, but neither air power nor body counts nor defoliation could break the will of the DRV, and the My Lai massacre of 16 March 1968 and the Tet Offensive that followed broke American public support for the war.

Examples in context

Example 1. Operation Rolling Thunder (2 March 1965 to 1 November 1968). Targeted bombing of North Vietnam dropped over 864,000 tonnes (more than the entire Pacific war). Mark Clodfelter (The Limits of Air Power, 1989) draws on USAF records to argue gradualism prevented decisive effect; civilian targets were excluded until late 1966. Fredrik Logevall and George Herring (America's Longest War, 5th ed. 2014) treat Rolling Thunder as the symbolic failure of attrition.

Example 2. The My Lai massacre (16 March 1968). Lieutenant William Calley's platoon killed approximately 504 unarmed civilians at Son My. Seymour Hersh broke the story in November 1969; Ron Haeberle's photographs appeared in Life on 5 December 1969. Christian Appy (Working-Class War, 1993, and American Reckoning, 2015) treats My Lai as the moment American public consciousness fractured. The Peers Commission Report (1970) documented systemic command failures.

Try this

Q1. Source A is an extract from Seymour Hersh's 13 November 1969 dispatch on My Lai. Using Source A and your own knowledge, explain the impact of American conduct on the war effort. [5 marks]

  • What the marker wants. Identify the My Lai massacre; cite the Peers Commission; link to anti-war sentiment.

Q2. Evaluate the extent to which American military strategy in Vietnam 1965 to 1968 was fundamentally misconceived. [25 marks]

  • What the marker wants. Weigh attrition, search and destroy, and Rolling Thunder against Westmoreland's body-count strategy; use Clodfelter, Herring, Logevall.

Q3. Compare the views of Mark Clodfelter and George Herring on the failure of American strategy. [10 marks]

  • What the marker wants. Clodfelter (operational failure of gradualism) versus Herring (strategic mismatch with political war); judgement.

Exam-style practice questions

Practice questions written in the style of NESA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Practice (NESA)15 marksAssess the effectiveness of United States military strategy in Indochina from 1965 to 1968.
Show worked answer →

Needs a clear judgment, dated evidence, and analysis across strategies.

Thesis
US military strategy from 1965 to 1968 inflicted huge damage on the enemy but failed to achieve its political objective, because attrition could not break Hanoi's will, air power could not interdict the Trail, and search and destroy alienated the rural population.
Attrition
Westmoreland's strategy assumed a "crossover point" at which PAVN/PLAF losses would exceed replacements. The Order of Battle dispute (1967) showed CIA estimates (around 600,000) suppressed by MACV in favour of lower figures (around 300,000). The body count corrupted units.
Search and destroy
Cedar Falls (Iron Triangle, January 1967) and Junction City (War Zone C, February to May 1967) inserted divisions into base areas; PAVN withdrew across the border. Around 5 million South Vietnamese were displaced by 1968.
Rolling Thunder
Around 864,000 tonnes dropped on the north from March 1965 to October 1968, more than the European theatre in WWII. The POL campaign of 1966 destroyed 70 per cent of north Vietnamese oil storage; PRC and Soviet imports replaced it.
Civilian experience
Around 2 million Vietnamese civilians died across the war. Operation Ranch Hand sprayed around 20 million gallons of defoliants from 1962 to 1971. The My Lai massacre (16 March 1968) killed around 504 civilians.
Tet and the verdict
Tet was a military victory for MACV but a political defeat. Cronkite's broadcast of 27 February 1968 called it a stalemate; Johnson on 31 March 1968 stopped Rolling Thunder above the 20th parallel and withdrew from the race.

Markers reward My Lai, the body count critique, and the political verdict.

Practice questions

Original practice questions graded from foundation to exam level, each with a full worked solution. Try them before revealing the solution.

foundation3 marksOutline the main features of General Westmoreland's strategy of attrition from 1965 to 1968.
Show worked solution →

A 3-mark "outline" wants three distinct, correctly stated features.

Attrition and the crossover point
Westmoreland aimed to kill PAVN/PLAF faster than Hanoi could replace them, reaching a "crossover point" that would force collapse.
Search and destroy
Helicopter-borne sweeps (Cedar Falls and Junction City, 1967) pushed large forces into enemy base areas to find and destroy units.
The body count
Success was measured by enemy dead and kill ratios rather than ground held, which corrupted reporting.
Marking criteria
1 mark each for three distinct features stated accurately; do not simply narrate one battle.
foundation4 marksExplain why Operation Rolling Thunder failed to achieve its objectives.
Show worked solution →

A 4-mark "explain" needs a cause-and-effect chain with specific evidence.

The objective
Rolling Thunder (2 March 1965 to 1 November 1968) aimed to break Hanoi's will and cut the flow of men and supplies south, dropping around 864,000 tonnes of bombs.
Gradualism
Targets were graduated and approved at Washington "Tuesday lunch" meetings; Hanoi, Haiphong, the dykes and the Chinese border buffer were off-limits for much of the war, so the campaign never delivered a decisive shock.
Resilience and resupply
The POL campaign of 1966 destroyed around 70 per cent of oil storage, but PRC and Soviet imports replaced it; SAM-2s and MiG-21s from 1966 inflicted heavy aircraft losses.
The result
The Ho Chi Minh Trail kept flowing and DRV morale held, so air power could not substitute for a political solution.
Marking criteria
1 mark for the objective; 1 mark for gradualism/off-limits targets; 1 mark for resupply/air defences; 1 mark for linking these to the failure.
core5 marksSource A (paraphrased, owned): An American war correspondent reporting from the central highlands in 1967 described how a battalion would sweep a village, count the enemy dead for the daily tally, and then withdraw by helicopter, leaving the same ground to be contested again within weeks. Using Source A and your own knowledge, explain the limitations of the United States strategy of attrition. [5 marks]
Show worked solution →

A 5-mark "explain ... using the source" wants the source decoded, then linked to own knowledge.

Decode the source
The correspondent captures the central flaw of attrition: forces measured success by the body count, then abandoned the cleared ground, so search and destroy returned territory to the enemy instead of holding it.
Own knowledge
Cedar Falls (January 1967) and Junction City (February to May 1967) inserted divisions into base areas, but PAVN withdrew across the Cambodian border into the Fishhook and Parrot's Beak and returned later. The body count corrupted reporting and the "crossover point" never came, because Hanoi accepted enormous losses.
The limitation
Attrition treated a political, revolutionary war as a conventional one; killing more of the enemy could not break Hanoi's will or hold the population, and the displacement of around 5 million southerners by 1968 alienated the very people pacification needed.
Marking criteria
1 mark for reading the source as the sweep-and-withdraw flaw; 1-2 marks for own knowledge (Cedar Falls/Junction City, sanctuaries, body count); 1 mark for the crossover-point failure; 1 mark for the broader limitation (political war, civilian alienation).
core5 marksSource B (paraphrased, owned): A later historian argues that the conventional United States Army fought the war it wanted rather than the war it had, applying a big-unit, firepower-heavy doctrine designed for the plains of Europe to a rural insurgency that demanded patient population security. Using Source B and your own knowledge, assess the usefulness of this interpretation for understanding why US strategy failed. [5 marks]
Show worked solution →

A 5-mark "assess the usefulness" question rewards origin/perspective plus own knowledge, ending in a judgement.

Perspective
Source B is the counter-insurgency critique associated with Andrew Krepinevich (The Army and Vietnam, 1986): the Army misapplied conventional doctrine. It is useful because it explains the mismatch between means and ends rather than blaming individual battles.
Corroboration from own knowledge
It fits the record: attrition and the body count, search and destroy sweeps that did not hold ground, and the priority of firepower (Rolling Thunder, free fire zones, defoliation) over population security. CORDS pacification was secondary and late (from May 1967).
Limitation
The view can understate factors beyond doctrine: the off-limits targets and gradualism imposed by Washington, the sanctuaries in Cambodia and Laos, and Hanoi's willingness to absorb losses. Lewis Sorley (A Better War, 1999) argues a better approach under Abrams from 1968 still could not overcome the collapse of will at home.
Judgement
Highly useful for diagnosing the doctrinal mismatch, but it must be read alongside the political constraints and the enemy's resilience, which a purely doctrinal account underplays.
Marking criteria
1 mark for identifying the counter-insurgency perspective (Krepinevich); 1-2 marks for corroborating own knowledge; 1 mark for a limitation (Sorley/political constraints); 1 mark for a judgement on usefulness.
core6 marksAssess the role of Australia and other allies in the conduct of the war from 1965 to 1968.
Show worked solution →

A 6-mark "assess" wants a short, evidenced judgement, not just a list.

Australia
Committed combat troops on 29 April 1965 under Menzies, citing SEATO and forward defence. The 1st Australian Task Force operated from Nui Dat in Phuoc Tuy from June 1966; peak strength was around 8,500. At Long Tan (18 August 1966) D Company 6RAR held off a far larger force (18 Australians, around 245 enemy killed). Australian doctrine stressed patrolling, ambush and population engagement, and Phuoc Tuy stayed relatively secure - a contrast to US firepower sweeps.
Other allies
South Korea (peak around 50,000, the Tiger and Capital Divisions, a brutal counter-insurgency reputation), Thailand (around 11,000), the Philippines (around 2,000 civic action) and New Zealand (around 550, attached to 1ATF). South Vietnam fielded an ARVN of around 1.1 million by 1968 with mixed quality.
Judgement
The allies gave the war the appearance of "Free World" solidarity and, in the Australian case, a more discriminating method, but they were small relative to the around 536,000 US troops and could not change the strategic outcome. Their domestic significance (Australian conscription and the 1970-1971 Moratoriums) was as important as their military weight.
Marking criteria
1-2 marks for the Australian commitment (dates, Phuoc Tuy, Long Tan); 1-2 marks for other allies with figures; 1 mark for the contrast in method; 1 mark for a judgement on overall significance.
exam25 marksEvaluate the view that the United States strategy in Indochina from 1965 to 1968 failed because it was fundamentally misconceived rather than poorly executed.
Show worked solution →

This is an extended-response/essay. Markers reward a sustained, evidence-based argument that addresses the "misconceived vs poorly executed" distinction directly and weaves in historiography - not a narrative.

Band-6 PLAN

  • Thesis. US strategy failed primarily because it was misconceived: attrition, search and destroy and graduated bombing answered a political, revolutionary war with conventional firepower, and no improvement in execution could have made that approach win. Execution flaws (the body count, gradualism, civilian harm) mattered, but they flowed from the underlying conception.
  • Argument 1 - The misconceived core (attrition). Westmoreland's "crossover point" assumed Hanoi would break when losses outran replacements; instead the DRV absorbed enormous casualties (Hanoi accepted attrition as the price of unification). Evidence: search and destroy (Cedar Falls, Junction City 1967) cleared ground it then abandoned; the sanctuaries in Cambodia and Laos let PAVN refit. The body count corrupted reporting (the 1967 Order of Battle dispute).
  • Argument 2 - Air power as the same error in the sky. Rolling Thunder (864,000 tonnes, 1965-1968) tried to coerce a pre-industrial society and interdict a footpath supply line; the POL campaign of 1966 destroyed 70 per cent of oil storage but imports replaced it. Gradualism (an execution flaw) made it worse, but even unrestricted bombing could not have broken a war of will - a conception error.
  • Argument 3 - Population and politics (the decisive misconception). Firepower (free fire zones, around 20 million gallons of defoliant, around 5 million displaced) alienated the rural population the war was meant to secure; pacification (CORDS, 1967) was late and secondary. My Lai (16 March 1968) and Tet exposed the gap between method and aim and broke US public support.
  • Historiography. Andrew Krepinevich (The Army and Vietnam, 1986) is the misconception thesis: the Army fought a conventional war it understood instead of the counter-insurgency it faced. Lewis Sorley (A Better War, 1999) is the rival execution thesis: under Abrams from 1968 a sounder pacification approach was winning, and the war was lost politically at home. Mark Clodfelter (The Limits of Air Power, 1989) shows the air war's failure was strategic, not merely operational.
  • Judgement. Weigh Krepinevich (misconceived) against Sorley (poorly executed and lost at home): execution flaws were real, but they were symptoms of a strategy that misread the nature of the war, so the misconception was primary. Better execution of the wrong strategy would still have failed.

MODEL PARAGRAPH (Argument 1)

The clearest evidence that the strategy was misconceived rather than merely mishandled lies in attrition itself. Westmoreland's premise was that there existed a "crossover point" at which PAVN and PLAF losses would outrun Hanoi's capacity to replace them, forcing collapse; the body count was built to measure progress towards it. Yet the premise misread the enemy. The DRV treated casualties as the acceptable price of national unification and never approached collapse, even as search and destroy operations such as Cedar Falls and Junction City in 1967 inflicted heavy losses - because those operations cleared ground only to abandon it, allowing PAVN to withdraw into its Cambodian sanctuaries and return. No refinement of execution could fix this: the strategy measured the wrong thing and conceded the population it was meant to protect. As Andrew Krepinevich argues in The Army and Vietnam (1986), the conventional Army fought the big-unit war it understood rather than the counter-insurgency it actually faced; the failure was therefore designed into the strategy, not introduced by its conduct.

Marker's note. A band-6 response keeps the "misconceived vs poorly executed" distinction in view throughout, ranking the two rather than describing the war, anchors every claim in dated evidence, and sets at least two historians in genuine tension (Krepinevich's misconception thesis against Sorley's execution thesis), reaching a graded judgement. Narrating the strategy without arguing which kind of failure it was caps the response in the middle bands.

exam25 marksTo what extent was American air power the most important reason for the failure of United States strategy in Indochina between 1965 and 1968?
Show worked solution →

This is an extended-response/essay. Markers reward a sustained, evidence-based argument that ranks air power against the other factors and weaves in historiography - not a narrative.

Band-6 PLAN

  • Thesis. Air power was a major but not the most important reason for failure: Rolling Thunder's inability to coerce Hanoi or cut the Trail symbolised the wider problem, but the decisive failure was the ground strategy of attrition and the alienation of the population, compounded by the collapse of will at home. Air power was the most visible failure, not the most important.
  • Argument 1 - The case for air power as decisive. Rolling Thunder dropped around 864,000 tonnes (1965-1968), more than the US dropped on Germany in WWII, yet gradualism and off-limits targets blunted it; the POL campaign of 1966 destroyed 70 per cent of oil storage but imports replaced it. If coercion from the air had worked, the ground war might have been unnecessary.
  • Argument 2 - Why the ground strategy mattered more. Attrition and search and destroy answered a revolutionary war with conventional firepower; the body count corrupted reporting and the "crossover point" never came. Sanctuaries in Cambodia and Laos and the displacement of around 5 million southerners showed firepower could not secure the population.
  • Argument 3 - The decisive factor: political will at home. Tet (1968), Cronkite's stalemate verdict and Johnson's 31 March 1968 withdrawal show the war was lost in American opinion. My Lai (16 March 1968) deepened the moral crisis. No military instrument, air or ground, could restore the political base for the war.
  • Historiography. Mark Clodfelter (The Limits of Air Power, 1989) argues gradualism crippled Rolling Thunder but that air power was always ill-suited to a war of will. George Herring (America's Longest War, 5th ed. 2014) treats the failure as a strategic mismatch with a political war. Andrew Krepinevich (The Army and Vietnam, 1986) locates the failure in the ground doctrine of attrition.
  • Judgement. Air power ranks among the proximate failures but depended on, and symbolised, the deeper errors of attrition and the loss of political will. Important, yes; the most important, no.

MODEL PARAGRAPH (Argument 3)

Air power's failure was spectacular, but the decisive blow fell at home rather than over Hanoi. By early 1968 the gap between official optimism - the November 1967 "light at the end of the tunnel" - and the televised shock of the Tet Offensive had drained the war of public support; Walter Cronkite's verdict that the conflict was "mired in stalemate" and President Johnson's announcement on 31 March 1968 that he would not seek re-election marked the collapse of the political base on which any strategy depended. The My Lai massacre of 16 March 1968, once exposed, sharpened the moral crisis. None of this could be repaired by bombing: even an unrestricted Rolling Thunder could not have rebuilt the consensus the war had lost. As George Herring argues in America's Longest War, the conflict was at root a political war the United States misread, so the failure of air power was a symptom of that mismatch rather than its cause.

Marker's note. A band-6 response keeps "to what extent" in view, ranking air power against attrition and the loss of political will rather than describing each, anchors claims in dated evidence (Rolling Thunder tonnage, Tet, 31 March 1968), and sets at least two historians in genuine tension (Clodfelter on the air war against Herring/Krepinevich on the deeper strategic and political failure), ending in a graded judgement.

ExamExplained