06/27/2011 11:53 am ET | Updated Aug 27, 2011

The Death of the Bush Doctrine

The Bush Doctrine is dead. It was mortally wounded in Iraq. It finally expired in Afghanistan.

The doctrine was promulgated by President George W. Bush in his second inaugural address on January 20, 2005, when he said, "The survival of liberty in our land increasingly depends on the success of liberty in other lands." That made it a matter of U.S. national security to turn other countries into democracies. Even to force democracy with guns and tanks, as we did in Iraq, and as we are trying to do in Afghanistan.

We're now seeing growing impatience with Afghanistan in the Republican Party. "I think we have learned that our troops should not go off and try to fight a war of independence for another nation," Mitt Romney said at this month's Republican debate in New Hampshire. Jon Huntsman advocates "an aggressive drawdown" of U.S. forces in Afghanistan. "I'm not sure the fate of our country is going to be determined on the prairies of Afghanistan," Huntsman said last week.

After the GOP debate, Sen. Lindsey Graham (R-SC) said, "I was disappointed that no one articulated why it matters if we win or lose in Afghanistan." Graham is close to Sen. John McCain (R-AZ), a leading proponent of the Bush Doctrine. McCain has been harshly critical of what he calls the "isolationist-withdrawal-lack-of-knowledge-of-history attitude that seems to be on the rise."

Last week, 225 House Republicans and 70 Democrats voted down a bill that would authorize the president to use force in Libya. The bill is being co-sponsored by John McCain in the Senate.

Public support for removing U.S. troops from Afghanistan "as soon as possible" is on the rise. A majority of Americans (56%) now favors withdrawal, according to a poll taken by the Pew Research Center. Republicans are divided: 53% favor keeping the troops there, while 43% want them to come home.

Why are Republicans turning against the Bush Doctrine? Partisanship has something to do with it. Afghanistan has become Obama's war, especially after the president announced a surge of troops in 2009. Then there are the polls showing the war losing public support.

But there's something going on here besides political expediency. There's also an issue of principle. The principle is small government. It is the guiding principle of the Tea Party movement, which is gaining ascendancy over the GOP.

Small government was never compatible with the Bush Doctrine. Tea Party activists call President Bush a "big government conservative." Under Bush, deficit spending mushroomed. We got a costly prescription drug program, the only new entitlement program ever initiated by a Republican president. And we got a huge increase in defense spending as a result of 9/11 and the wars in Afghanistan and Iraq.

Afghanistan is costing the U.S. more than $300 million a day. Rank-and-file Republican Members of Congress are surprisingly willing to consider serious cuts in defense spending. "I know there are sacred cows [in the defense budget]," freshman Rep. Adam Kinzinger (R-IL) told the Washington Post. "But we cannot afford them any more."

President Clinton used to call the United States "the world's indispensable nation." That is still true. The rule in world affairs is, unless the United States acts, nothing will happen. If the United States had not gone to war in 1991, Kuwait would be part of Iraq. If the U.S. had not acted in Bosnia, ethnic cleansing would never have been stopped. If the U.S. had not led an invasion of Afghanistan, the Taliban would still be in power, harboring al Qaeda terrorists.

President Obama pledges that the U.S. will continue to act. But from now on, we won't always do it on our own. And we will do it more cheaply.

Meanwhile, the Republican Party is facing a showdown between the forces that want to shrink government and the forces that favor an interventionist foreign policy. The doctrine of small government is trumping the Bush Doctrine. The Tea Party is shoving aside the neo-conservatives.

Why did the Bush Doctrine die? Because it was too expensive. And because we learned a painful lesson in Iraq and Afghanistan: the U.S. military is no good at nation-building. Back in 2000, in a campaign debate with Al Gore, then-Gov. Bush warned, "If we don't stop extending our troops all around the world in nation-building missions, then we're going to have a serious problem coming down the road." We didn't, and we do.