Thomas Donnelly writes in the Weekly Standard:

Today’s [U.S. military] stands at the end of a 30-year trail of investment in recruiting, retaining, and training the best people and providing them with world-class equipment. The fighting in our long war against global terrorism has been varied and exhausting, but the force has been sharpened to the cutting edge. The SEALs who killed bin Laden were prepared to succeed. . . . The irony, of course, is that Barack Obama — the commander in chief who owes his newfound martial reputation to a military built and maintained by his predecessors of both parties — is leading the charge to cut defense spending. His most recent proposal to eliminate $400 billion from future Pentagon budgets essentially doubles the cuts from his first two years in office. The long-term result will be a smaller, less-well-equipped and less-well-trained force. If President Obama continues to employ the force at current rates, it will be more rapidly run down.

It is not simply President Obama’s passion for defense cutting that should concern us, although the heft of the wrecking ball is troubling, indeed. The worry for those who reject the isolationist impulse and recognize the need for a robust U.S. presence in the world is that the Republicans might follow suit:

[I]f Obama’s 2012 opponent is the nominee of a quasi-isolationist, green-eyeshade GOP, Obama will be able to claim he’s the most assertive candidate for commander in chief.

We saw at Thursday night’s debate how easy it is to get applause by expressing a desire to bring our troops home. It is at times incoherently expressed. (Former New Mexico governor Gary Johnson proclaimed, “I’m not in favor of a timetable. I’m in belief that timetable should be tomorrow. I realize that tomorrow may involve several months.”) And certainly the isolationists who were on the stage in South Carolina (Herman Cain, Gary Johnson and Ron Paul) are not very credible contenders for the nomination. But what if a less kooky and more articulate “quasi-isolationist, green-eyeshade” candidate appeared on the scene?

The prospect of a libertarian/Paleo-conservatism alliance is real. And as a general election strategy running to the left of Obama on foreign policy and the right on domestic policy might be tempting. In his brief pre-campaign campaign, Mississippi Gov. Haley Barbour seemed inclined to go down that path. Sarah Palin has now discovered her inner Robert Taft. And most distressingly, the otherwise highly capable and thoughtful Indiana Gov. Mitch Daniels is suggesting, much like Obama, that the Pentagon could use some chopping and, like the liberals in Congress, that we need to pare down our overseas commitments, not for national security reasons but simply on the basis that they cost too much.

A nominee sporting such an outlook, I would suggest, will tear the GOP asunder. Religious conservatives (who take seriously the unique role and obligation of the United States in the world) and defense hawks would be aghast to hear a Republican nominee trying to match (or even outbid) Obama’s defense reductions. And those Republican lawmakers who are bravely resisting the drumbeat in favor of slashing defense would be undercut by their party’s standard-bearer, leaving them vulnerable to attack by Democrats eager to throw the presidential nominee’s positions up in their faces.

In sum, there are substantive and political reasons for Republicans to resist the temptation to abandon modern conservatism’s foreign policy (one that is grounded in moral values as well as a canny assessment of the danger of inaction). Whether they will do so depends in large part on the quality of the candidates and the strength of their arguments. If the internationalists are not forceful and effective in debunking the isolationists, as well as successful at the primary ballot boxes, the country and the party will suffer.