Press reports have suggested that Administration officials are trying to make Democratic voters forget that the Administration promised to start drawing down troops from Afghanistan in July 2011 by “pivoting” to the “aspirational goal” that “most” U.S. “combat troops” will be withdrawn by 2014. The Administration still says it will withdraw some troops in July 2011, but press reports suggest that the Administration may try to make this a “symbolic” withdrawal, not the “serious drawdown” (as Speaker Pelosi put it) involving “a whole lot of people” (as Vice-President Biden put it) that Democrats were led to expect.

But if these press reports about Administration strategy are correct, Administration political strategists may have another think coming. Democratic pollster Stan Greenberg suggests that continued escalation of the war in Afghanistan would be likely to draw a primary challenge, the Christian Science Monitor reports:

As Democratic pollster Stan Greenberg was leaving a Monitor breakfast last week, he was asked about the possibility that President Obama might face a Democratic primary challenge in 2012.

Mr. Greenberg’s two-word answer: “Watch Afghanistan.”

As the Monitor notes, a recent Quinnipiac University poll found that 62 percent of Democrats say US troops should not be in Afghanistan.

Note that the same Quinnipiac poll found military families split on the war, “with 49 percent backing the US role and 47 percent saying the troops should come home.” That suggests significant dissent among the troops, because if every GI Jane and Joe is telling Mom and Dad that the war makes sense and the prospects are good, you wouldn’t expect half of military families to say that US troops shouldn’t be there. Dissenting troops tend to produce dissenting veterans. Dissenting veterans tend to produce dissenting veteran candidates for office.

If Stan Greenberg thinks a Democratic primary is a serious prospect if the escalation of the Afghanistan war continues, then that’s a claim that cannot be dismissed. Greenberg has been studying elections for a long time, and is paid top dollar to be right more often than most other people.

A key reason that some folks don’t take this threat very seriously yet is that when they think of a primary challenge, their first thought is: “who is the candidate?” It’s a natural thought. If they can’t think who the candidate is, then it doesn’t seem like a serious threat.

But this misses the fact that the potential pool of credible candidates is actually quite large, and if you look back to the past, few people could have predicted well in advance who might emerge as a credible candidate.

To be a credible candidate for President, at least one of the following three attributes is minimally sufficient, in addition to being legally eligible and having a plausible message: a) you have a huge pile of money b) you are famous and have a big base of public support or c) you can rely upon the support of a big organization.

Now, of course, most Americans don’t have any of these three attributes. Relative to the entire population, they are rare attributes. But relative to the fact that you only need one candidate for a primary challenge, the set of Americans who have at least one of these attributes is quite large.

How many Americans would have predicted in the summer of 1991 that a year later billionaire Ross Perot would be leading President George H. W. Bush and Governor Bill Clinton in national polls? How many Americans would have predicted in the spring of 1987 that Jesse Jackson would win seven Democratic primaries and four caucuses a year later, including Delaware, Michigan, and Vermont, leading the New York Times to call 1988 the “Year of Jackson“? How many Americans would have predicted in late November 1967 when Senator Eugene McCarthy announced his candidacy for President that he would nearly defeat incumbent President Johnson in the New Hampshire primary four months later, amidst rising Democratic discontent about Vietnam? How many Americans would have predicted in 1932, when FDR was first elected promising to balance the budget, that the threat of Huey Long’s presidential candidacy would help produce the New Deal, with Roosevelt adviser Raymond Moley reporting that FDR said he wanted to “steal Long’s thunder“?

This history suggests that if conditions are right, candidates are likely to emerge. Therefore, it may not be so easy to sweep President Obama’s July 2011 drawdown promise into the dustbin of history. A Democratic Presidential candidate has a big megaphone. If some Americans forget that President Obama promised to withdraw troops from Afghanistan in July 2011, a Democratic primary candidate is likely to remind them.

If you don’t want to see this scenario play out, tell President Obama to keep his promise for a “serious drawdown” of troops in 2011.

Robert Naiman is Policy Director at Just Foreign Policy.