What determined the outcome of the conflict?

Leadership, strategy and tactics, mobilization of resources, and technology.

Keeping allied states cooperating on shared strategy despite having different goals and political systems.

Churchill, Roosevelt and Stalin met at conferences (Tehran 1943, Yalta 1945) to agree joint strategy, including opening a Western Front via D-Day (1944).

Small, hidden attacks by irregular forces that avoid open battles, used to wear down a stronger enemy over time.

Protracted guerrilla war avoided battles the US would win outright, and steadily eroded American political will until troops withdrew in 1973.

The US built over 300,000 aircraft and 88,000 tanks by 1945, giving the Allies overwhelming material superiority when combined with Lend-Lease aid to allies.

Radar (early warning of air raids), air power (destroying German industry and troop movements), and codebreaking (reading German Enigma communications).

Jungle terrain, tunnel networks, and an enemy blended into the civilian population blunted the effect of helicopters, napalm and air power like B-52 bombing.

In WWII, Allied resources were decisive because strategy and political will used them effectively. In Vietnam, US resource superiority failed because it was not matched by a suitable strategy against an insurgency.

Rising US casualties and televised coverage eroded American public and congressional support, forcing withdrawal, while North Vietnamese leadership sustained will for a long war of independence.

US technology changed how the war was fought, but the continuity of guerrilla tactics (used by insurgents for centuries) blunted that change, unlike in WWII where technology directly enabled victory.

A strategy of gradually wearing down an enemy's forces and resources through sustained, often conventional, fighting rather than a single decisive blow.