After America’s ignominious defeat and hurried departure from Vietnam in 1973 — when the world’s richest and mightiest nation was humbled by the stolid determination of ill-equipped, ideologically inspired peasants — it was generally assumed the United States would not wage war again until the lessons of the Viet Cong victory were taken to heart.

When Soviet forces hastily retreated with a bloody nose from their nine-year occupation of Afghanistan in 1989, similar lessons were suggested about the impossibility of militarily holding a country with a universally hostile population.

In his stealth occupation of Crimea and eastern Ukraine, President Vladimir Putin of Russia appears to have learned the lessons of both Vietnam and Afghanistan.

Successive U.S. presidents, however, seem to have failed to understand how military strategy was forever changed by what happened in those two chastening conflicts. Rather, they have gone on to repeat their predecessors’ mistakes.

That’s not all. The fleet of U.S. stealth bombers ($810 million each) and the fleet of nuclear submarines ($8.2 billion each) armed with Trident nuclear missiles ($31 million each) are of little use against Russian intelligence agents provocateurs disguised as Ukrainian protesters arriving by civilian airliner.