Payback is a poor excuse for a foreign policy. That's one of the lessons I derive from reading Steve Coll's Ghost Wars : The Secret History of the CIA, Afghanistan, and Bin Laden, from the Soviet Invasion to September 10, 2001.
I'm only 2/3 of the way through this very detailed history, but some things are already clear. One is that in 1979, when the Soviet Union invaded Afghanistan to ensure it would have a friendly government in a strategically located country, the U.S. was still licking its wounds from Vietnam. Zbigniew Brzezinski, President Carter's national security advisor, was still viewing the Soviets as the people who invaded Eastern Europe. The Carter administration felt betrayed by the Soviet move, and they took it personally. They saw Afghanistan not as a country of its own, with a people whose destiny mattered, but as a place where they could get back at the U.S.S.R. and humiliate them as the U.S. had been humiliated earlier in the decade.
The U.S. armed violent Islamic fundamentalists to fight against the Soviets in Afghanistan. With what result? Some of those became the warlords who carved up Afghanistan in the 1980's and early 1990's, after Gorbachev decided the war in Afghanistan was unwinnable: Hekmatyar, Massoud, etc. Some became the jihadists who replaced those warlords. We know them as the Taliban.
For over two decades, to spite the Soviet Union, the U.S. condemned Afghanistan to civil war and chaos. President Obama today is making tough choices (and I believe, wrong choices) about sending troops to Afghanistan partly because of the problems the U.S. made.
We did not create those problems all by ourselves, however. That's the subject of a future post.