Photo: Melina Mara/The Washington Post via Getty Images

One day this spring, over lunch in Chicago, David Axelrod offered up a concise summary of Team Obama’s prevailing view about the race ahead against Mitt Romney. “We have the better candidate, and we have the better argument,” Axelrod told me. “The question is just whether the externalities trip us up.” For months before that and every day since, the litany of potential exogenous shocks—from the collapse of the eurozone to a hot conflict between Israel and Iran to a succession of brutal jobs reports—has kept Axelrod and his colleagues tossing and twitching in their beds at night. For all their overt confidence, the Obamans are also stone-cold paranoiacs, well aware of the iron law of politics enunciated long ago by the poet Robert Burns: “The best-laid schemes o’ mice an’ men / Gang aft agley.” Which, for those unversed in archaic Scottish, translates roughly as “Shit happens.”

And so it does, with the past week proving another maxim: that when shit rains, shit pours. In the space of 72 hours, what began, horrifically enough on September 11, with the murder of four Americans (including one of our best and bravest, Christopher Stevens, the U.S. ambassador to Libya) at the consulate in Benghazi spiraled into a region-wide upheaval, with angry Muslim protests directed at American diplomatic missions erupting in sixteen countries. Suddenly, the president was facing just the kind of externality that his team had been bracing for: a full-blown ­foreign-policy crisis less than eight weeks out from Election Day. And a campaign marked by stasis and even torpor was jolted to life as if by a pair of defibrillator paddles applied squarely to its solar plexus.

Moments like this are not uncommon in presidential elections, and when they come, they tend to matter. For unlike the posturing and platitudes that constitute the bulk of what occurs on the campaign trail, big external events provide voters with something authentic and valuable: a real-time test of the temperament, character, and instincts of the men who would be commander-in-chief. And when it comes to the past week, the divergence between the resulting report cards could hardly be more stark.

Anyone doubting the potential significance of that disparity need only think back to precisely four years ago, when the collapse of Lehman Brothers triggered a worldwide financial panic. In the ten days that followed, Obama put on a master class in self-possession and unflappability under pressure; his rival, John McCain, did the opposite. When the smoke cleared, the slight lead McCain had held in the national polls was gone and Obama had seized the lead. Though another month remained in the campaign, the race was effectively over.

For Romney, the first blaring sign that his reaction to the assault on the consulate in Benghazi had badly missed the mark was the application of the phrase “Lehman ­moment” to his press availability on the morning of September 12. Here was ­America under attack, with four dead on foreign soil. And here was Romney, defiantly refusing to adopt a tone of sobriety, solemnity, or seriousness, instead attempting to score cheap political points, doubling down on his criticism from the night before that the Obama administration had been “disgraceful” for “sympathiz[ing]” with the attackers—criticism willfully ignoring the chronology of events, the source of the statement he was pillorying, the substance of the statement, and the circumstances under which it was made.

That the left heaped scorn on Romney’s gambit came as no surprise. But the right reacted almost as harshly—with former aides to John McCain, George W. Bush, and Ronald Reagan creating an on-the-record chorus of disapproval, while countless other Republican officials and operatives chimed in anonymously. “This is worse than a Lehman moment,” says a senior GOP operative. “­McCain made mistakes of impulsiveness, but this was a deliberate and premeditated move, and it totally revealed Romney’s character; it revealed him as completely craven and his candidacy as serving no higher purpose than his ambition.”

This bipartisan condemnation would have been bad enough in itself, but its negative effects were amplified because it fed into a broader narrative emerging in the media across the ideological spectrum: that Romney is losing, knows he is losing, and is starting to panic. This story line is, of course, rooted in reality, given that every available data point since the conventions suggests that Obama is indeed, for the first time, opening up a lead outside the margin of ­error nationally and in the battleground states. So the press corps is now on the lookout for signs of desperation in Romney and is finding them aplenty—most vividly in his reaction to Libya, but even before that, in his post-convention appearance on Meet the Press, where he embraced some elements of Obamacare (only to have his campaign walk back his comments later the same day).

The peril to Romney’s candidacy of being seen through the lens of desperation can’t be overstated. The paramount strategic objective of any campaign is to maintain control of the candidate’s public image—and if the media filter begins to view his every move through a dark or unflattering prism, things can quickly spin out of control, to a point where nothing he says or does is taken at face value. “Romney is in a very bad place,” says another senior Republican strategist. “He’s got the Republican intelligentsia second-guessing him, publicly and privately. The party base has never trusted him and thinks that everything bad it ever thought about him is being borne out now. And he’s got the media believing that he can’t win. He’s right on the edge of a self-­fulfilling downward spiral.”

Whether Romney can resist that spiral in the two weeks between now and the first presidential debate is an open question—but there’s no doubt that the pressure on him to win that debate decisively is now almost overwhelming. “If he doesn’t, you’ll see the whole thing start to unravel pretty quickly, à la Dole in 1996,” says a third GOP strategist, arguing that Romney’s fund-­raising will dry up and the expected flood of money from conservative super-pacs will be reduced to a trickle.

None of which is to say that Romney is alone in confronting serious challenges owing to these events. For Obama, you could argue, the circumstances are equally demanding. In ­almost every way, running as an incumbent confers marked advantages: the power and stature of the office, the ­ability to demonstrate governing capacity rather than just stipulate it, the infrastructure that comes with the White House, including the use of that great big plane.

But when crises are roiling halfway around the globe, those advantages are severe­ly tempered. No longer is full-time, single-minded campaigning an option—nor should it be. Yet so far Obama has managed to strike a subtle balance on the hustings: suitably somber, resolute, and almost Bushian in his combination of tough talk (“I want people around the world to hear me: To all those who would do us harm, no act of terror will go unpunished”), patriotic swagger, and partisan contrast with his opponent.

If circumstances in the Middle East worsen, however, Obama’s performance will be measured under the magnifying glass of 24/7 campaign coverage. And those circumstances will inject an uncomfortable degree of unpredictability into an environment that he and his leaving-nothing-to-chance advisers would dearly prefer to be as stable as ­possible—and put on the line one of the areas of policy, national security and foreign policy, in which his lead over Romney has always been yawningly wide.

Making matters all the dicier for Obama is the possibility that, beyond the embassy protests, he may also have to cope with a related headache induced by Israel and Iran—and in particular by Bibi Netanyahu. In the days before the Libya tragedy, Netanyahu launched a broadside plainly aimed at the U.S. over what he sees as its spinelessness in working with Israel to halt the Iranian nuclear program by any means necessary. To some, the broadside had all the appearances of Netanyahu trying not just to place a thumb on the scale in America’s election but of slamming his whole hand on it. And there is no paucity of evidence to suggest Netanyahu would much prefer Romney, whom he has known for years, to win; his warm embrace of the Republican nominee when he visited Israel in July, which was tantamount to an endorsement, was ­remarkable in its brazenness and nearly without precedent in the modern annals of presidential politics.

Still, there are signs that Netanyahu may simply be trying to exercise what ­leverage he has now because he knows it will soon be diminished. As a former American intelligence officer who met ­recently with top Likud officials put it to Politico, “They are grimly accepting the reality Mitt won’t win.”

Take out the adverb in that sentence and you have a pretty decent encapsulation of the emerging cross-partisan conventional wisdom here at home—one that Romney needs to do something fast to shatter, or it may harden into concrete.

E-mail: jheilemann@gmail.com.