Will ‘September surprise’ or debate gaffe shake up tight race?

After the political conventions had ended and the monthly jobs report was out, a senior White House aide was asked what would happen to change the presidential contest between now and Oct. 3.

His answer: “Nothing.”

That’s a reasonable guess. After all, the matchup between President Obama and Mitt Romney hasn’t budged significantly since the Republican challenger secured his party’s nomination back in the spring.

INTERACTIVE MAP: Tally up the battleground states
But that doesn’t mean something can’t or won’t happen before Oct. 3 (a red-letter date; see No. 5, below) that shakes up a tight race or even decides the election. Here are five possibilities:

1. A September surprise

By definition, it’s impossible to foresee exactly what external shock might change the contest in a decisive way. A crisis abroad, a scandal involving one of the candidates or something in the financial world are among the possibilities. At this point four years ago, Obama and John McCain were locked in a close and competitive tussle. Then Lehman Brothers declared bankruptcy on Sept. 15, the financial crisis deepened, stock markets plunged and McCain never really recovered.

2. Will Obama’s bounce last?

There is accumulating evidence that the Democratic convention generated at least a moderate bounce in the polls for Obama. The latest Gallup tracking poll, released this weekend, shows Obama opening up a 4 percentage point lead in a measure that had been virtually deadlocked. The poll has a margin of sampling error of plus or minus 3 percentage points.

Since the poll is a seven-day average, it contains data collected before the Democratic National Convention opened in Charlotte, N.C. That suggests Obama’s lead could expand in coming days. Romney, by contrast, got little or no bump from his convention (Gallup’s numbers never budged). Still, convention bounces usually go away. It may take another week, or even longer, to say with more certainty whether Obama gained a lasting advantage.

3. Can Romney stay on message?

From the start, Romney’s chances of unseating Obama have depended on one factor above all: how voters feel about a weak economy that hasn’t generated enough jobs to lower a persistently high unemployment rate. Most Americans believe the country has gotten seriously off on the wrong track, an ominous statistic for an incumbent president.

But Romney has repeatedly lost his focus on jobs, most recently when he chose Paul D. Ryan as his running mate and shifted the campaign debate to Medicare, a risky issue for Republicans. On Sunday, Romney will make a high-profile appearance on NBC’s “Meet the Press.” He’s shown an aptitude for avoiding blunders on other TV interview programs and, for that reason, is unlikely to make the wrong kind of news. A gaffe is one of the last things he needs now.

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4. Shifting moves on the electoral map

Throughout the summer, no more than a dozen states have received virtually all the attention of both campaigns and the “super PACs” supporting them. Hundreds of millions of TV advertising dollars have already been spent in these battleground states. They’re also where the candidates have returned, time and again, to keep supporters motivated and to woo the tiny slice of the electorate that remains undecided.

Over the next few weeks, some states on the outer edges of the electoral map may fall by the wayside as time begins to run short, campaign bank accounts are stretched and the candidates sharpen their focus on a smaller number of must-win states. Republicans are predicting that Obama and the Democrats will soon abandon North Carolina, where he won by just 14,000 votes last time. Democrats are keeping close track of Romney’s activity in states that favor Democrats in presidential elections but could be up for grabs this time. The ones to watch: Wisconsin, Michigan and Pennsylvania.

5. The debates

Other than Election Day, the most important dates on the campaign calendar are the four televised debates -- three presidential and one vice presidential. Thanks to the 20 debates he endured during the Republican primaries, Romney is the more seasoned debater. He performed well when it mattered and avoided self-inflicted damage.

His first encounter with Obama will be Oct. 3 in Colorado, a hotly contested swing state. Historically, a challenger benefits when he gets to stand on the same stage with the president for the first time. Voters view him in a new light and his stature suddenly seems more presidential. That’s why Romney should benefit once debate season gets under way, unless he stumbles.

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paul.west@latimes.com

Twitter: @paulwestdc