At a time when U.S. forces are engaged in combat on three continents, one would think that national security would be front and center in any debate between those vying to become the next commander in chief.  But national security received scant attention at Monday’s Republican primary debate in New Hampshire — and what limited discussion took place was deeply troubling.

This week, The Post’s Jackson Diehl asked whether the GOP will “nominate a dove” in 2012, citing the failure of any of the candidates at Monday’s debate to speak out in support of President Obama’s military intervention in Libya. I support the Libya intervention, but there can be legitimate differences over this policy.  More worrisome is the growing sentiment for withdrawal from a country where there should be no question among Republicans that the United States has vital interests at stake: Afghanistan.

During the debate, GOP front-runner Mitt Romney was asked by a voter, “Osama bin Laden is dead. We’ve been in Afghanistan for 10 years. Isn’t it time to bring our combat troops home from Afghanistan?” Romney instantly replied: “It’s time for us to bring our troops home as soon as we possibly can, consistent with the word that comes to our generals that we can hand the country over to the Taliban military in a way that they’re able to defend themselves. Excuse me, the Afghan military to defend themselves from the Taliban. That’s an important distinction.” 

It is indeed, and Romney’s faux pas was unintentionally revealing — because handing Afghanistan over to the Taliban is exactly what a precipitous withdrawal would do. It is also telling that Romney’s instinct was to argue for withdrawal rather than explain why it is essential that America succeed in Afghanistan, or lay out the consequences of failure in the country where al-Qaeda planned the attacks of Sept. 11, 2001. To the contrary, Romney explained that the lesson he had taken from our experience in Afghanistan is that “our troops shouldn’t go off and try and fight a war of independence for another nation.” Does this mean that Romney thinks the United States should not have sent troops to deny al-Qaeda a safe haven by removing the Taliban from power in the first place?

Even more telling is the fact that this was the extent of the discussion on Afghanistan in the entire two-hour presidential debate. The only other mentions came when Newt Gingrich said, in a discussion on immigration, “We ask the National Guard to go to Afghanistan. Somehow we would have done more for American security if we had had the National Guard on the [U.S.] border,” and when Ron Paul predictably declared “We should think about protecting our borders, rather than the borders between Iraq and Afghanistan.” (Note to Paul: There are no borders between Iraq and Afghanistan — though there is a big country called Iran that is pursuing nuclear weapons. There was no discussion of that in the debate either). 

Not one candidate stepped forward to argue for prosecuting the Afghan war to a successful conclusion. Not Michele Bachmann, who had previously criticized Obama for failing to speak of “victory” when announcing his Afghan surge. Not even Tim Pawlenty, who has previously called for “strategic patience” in Afghanistan and argued, “If we are serious about what this means about terrorism . . . and our national security interests, then we need to be serious about seeing it through . . . .” (To his credit, Pawlenty did defend U.S. missile strikes in Yemen and the liberation of Iraq, which he called “one of the shining examples of success in the Middle East”). 

Although he was not at the debate, former Utah governor Jon Huntsman — who is preparing to announce his candidacy next week — argued in a CNN interview Sunday for a faster timetable for pulling U.S. troops from Afghanistan than the one President Obama has in mind: “When you look at Afghanistan, can we hang out until 2014 and beyond? You can, if you’re willing to pay another quarter of a trillion dollars to do so . . . . If it isn’t in our direct national security interest and if there isn’t a logical exit strategy and if we don’t know what the cost is going to be in terms of money and human lives, then I think you have to say it’s probably time we reevaluate this. My hunch is the American people want to be out of there as quickly as we can get it done.” 

And therein lies the source of the GOP flirtation with retreat in Afghanistan. A recent Washington Post/ABC News poll found that while a majority of Republicans still say that the war in Afghanistan is worth the costs, 59 percent favor withdrawing a substantial number of troops this summer (compared to 89 percent of Democrats and 72 percent of Independents). This can be taken by the candidates as an opportunity for pandering or an opportunity for leadership.  While Republicans are not immune to war fatigue, there is no clamor for retreat within the party, unlike the case with the Democrats. If Republican candidates were to make the case for success in Afghanistan, they would likely find a receptive audience among Republican primary voters. 

It is worrisome that, so far at least, few seem willing to do so.