The current war in Iraq will generate a ferocious blowback of its own, which -- as a recent classified CIA assessment predicts -- could be longer and more powerful than that from Afghanistan. Foreign volunteers fighting U.S. troops in Iraq today will find new targets around the world after the war ends.

During Richard Nixon's first term, when I served as secretary of defense, we withdrew most U.S. forces from Vietnam while building up the South's ability to defend itself. The result was a success -- until Congress snatched defeat from the jaws of victory by cutting off funding for our ally in 1975. Washington should follow a similar strategy now, but this time finish the job properly.