So far, of the declared candidates for president, the only one who voted for the Iraq War is the Democrat.

I recently made that observation on Twitter and the response was instructive. I will refrain from reprinting the more piquant language from Hillary Clinton’s supporters, but one common theme was that I am a fool. Sens. Ted Cruz, Rand Paul and Marco Rubio weren’t in the Senate for the Iraq war vote, many shrieked.

Well, exactly.

In case you haven’t been paying attention, you might be interested to know that the Iraq War was not popular, especially among Democrats. If you had to pick a single position that allowed Barack Obama to pull ahead in the 2008 Democratic primaries, his opposition to the war would almost certainly be it.

It still looms large in the liberal mind: Obama frequently uses the Iraq War as proof of his foreign policy wisdom, which is otherwise unearned by evidence or argument.

For instance, humiliated of late by the rise of the Islamic State – a group he’d glibly dismissed as a negligible “jayvee team” – Obama now concedes it’s a real problem but blames its rise entirely on the war.

“Two things: One is, ISIL is a direct outgrowth of al-Qaida in Iraq that grew out of our invasion,” Obama told VICE News last month. “Which is an example of an unintended consequence. Which is why we should generally aim before we shoot.”

Obama is merely the headmaster of this cheap and lazy school of thought. Blaming the Iraq War for the world’s problems or using it as a way to deflect legitimate criticism of Obama’s foreign policy remains the primary rhetorical gimmick for many liberals. For instance, Clinton ur-spinner James Carville dismissed Mrs. Clinton’s email scandal as “diddly squat.” When MSNBC’s Mika Brzezinski asked if he’d say the same thing if Dick Cheney had a stealth server, Carville spluttered in response that Cheney had started the Iraq War.

Much has been written about Jeb Bush’s challenge. Unfair as it might be, Bush must run as, well, a Bush. His last name is a burden for several reasons, but chief of among them is the unpopularity of the Iraq War.

In a debate with Clinton, whatever barbs Bush might hurl at the Obama-Clinton foreign policy record – and there is no shortage of pointed ones to be thrown – Clinton would probably be able to deflect them by dredging up “your brother’s war” (even though she might wisely avoid familial guilt-by-association arguments, given her own baggage in this regard).

The weird thing is, Clinton has far more responsibility for the Iraq War than Jeb Bush does. Meanwhile, none of the potential GOP presidential hopefuls voted for the war in 2002. Scott Walker was the Milwaukee County executive; Marco Rubio was in the Florida House of Representatives; Chris Christie was a U.S. district attorney; Ted Cruz was a policy wonk at the Federal Trade Commission; Rand Paul and Ben Carson were practicing surgeons. And so on.

Of course, one could argue that many would have voted for the war (probably true of Rubio, probably untrue of Paul). But that’s all hypothetical. Not so with Clinton. She voted for it, defended it in the well of the Senate, and arguably lost the primaries in 2008 because she refused to apologize for her vote.

Personally, I don’t think support for the war should be disqualifying. And I have no doubt that most antiwar Democrats will nonetheless work through their cognitive dissonance and vote for Clinton. They hardly put up much protest when antiwar Obama selected Clinton, Joe Biden and John Kerry, all of whom voted for the war, as his top foreign policy gurus.

Perhaps this generational wave of post-Iraq Republican politicians says something interesting about the GOP? Likewise, perhaps Clinton’s support for the war – until she apologized in her 2014 memoir – says something about her? Reasonable (and unreasonable) people will differ on all that.

But Clinton’s support for the war underscores a broader vulnerability. Unlike her probable opponents, she’s truly a creature of yesterday’s battles. From the fight over “Hillarycare,” to the endless scandals of her husband’s administration, to the ugly brawls over the Iraq War, Hillary Clinton has been a partisan fixture of Washington at its most exhausting and ugly moments. A Midwestern road trip in a van dubbed “Scooby,” even one punctuated by burrito breaks, won’t make people forget that, nor will defensive outbursts from her supporters stop her critics from pointing it out.

Jonah Goldberg is a fellow at the American Enterprise Institute and a senior editor of National Review. You can write to him at goldbergcolumn@gmail.com, or via Twitter @JonahNRO.

(C) 2015 TRIBUNE CONTENT AGENCY, LLC