Over $1 trillion so far - and we're much less safe. Tyler Cowen explains:

Foreign governments, of course, drew the obvious lesson from our debacle -- and from our choice of target. The United States invaded hapless Iraq, not nuclear-armed North Korea. To the real rogues, the fall of Baghdad was proof positive that it's more important than ever to acquire nuclear weapons -- and if the last superpower is bogged down in Iraq while its foes slink toward getting the bomb, so much the better. Iran, among others, has taken this lesson to heart. The ironic legacy of the war to end all proliferation will be more proliferation.

The bottom line is clear, Mr. President: The more you worried about the unchecked spread of doomsday weapons, the stronger you thought the case was for war in the first place. But precisely because you had a point about the need to stop nuclear proliferation, you must now realize that the costs of a failed war are far higher than you've acknowledged.

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