They were the hot wars in a cold war against communism: Korea, Congo, Vietnam, Cuba, El Salvador, Nicaragua, Angola, Grenada, even Afghanistan.
Each was different. Each took a heavy toll. But each more or less helped to end the 45-year-long cold war.
Now, after this latest war in Afghanistan, a list of potential wars in the campaign against global terrorism is being drawn up in Washington.
Is Yemen next? Somalia? A few islands in the Philippines or Indonesia? Perhaps Iraq?
Tough choices. Any war is messy, but it's even messier when an enemy is not really a nation but a netherworld network of monied militants who will resort to anything, even suicide and chemical weapons, and who hide out in Muslim sanctuaries of chaotic countries.
Taking down just Al Qaeda may not be all that simple. This American-led war on global terrorism could unleash all sorts of wars that the US may regret, much like the Vietnam war. One problem lies in defining the meaning of "global terrorism."
Take, for instance, last week's suicide attack on India's Parliament, which left 14 people dead. India claims it has evidence that all five of the suicide attackers were Pakistani and members of the Lashkar-e-Taiba and Jaish-e-Mohammed terrorist groups, which are based in Pakistan.
Both Pakistan and those groups deny any involvement in the attack. Yet they have, in the past, fought India for control of largely Muslim Kashmir.
If India's evidence is accurate, how should it - and the US - respond to this case of international terrorism?
The US can hardly let India strike Pakistan now, as the US did the Taliban in Afghanistan, when Pakistan is helping the US track down Al Qaeda. Both Pakistan and India have nuclear weapons; the US can't just let a war erupt.
Yet one militant group operating in Kashmir, Harkat-ul Mujahideen, is on a list of 27 terrorist entities whose assets were frozen by the US. And India claims those behind the Dec. 13 attack have ties to Al Qaeda.
All of this is taking place when a US aircraft battlegroup is making an unprecedented port visit to Bombay, part of warming defense ties between India and the US.
President Bush warned of a long campaign. Now he must be more specific, being careful that loaded words don't unleash unnecessary wars.