The polls suggest that the next president, whether it's Mitt Romney or Barack Obama, will win by a slim margin. And some observers suggest that this could affect how the next president actually governs: Absent the sort of landslide that delivers a clear mandate for radical change, both could be more inclined to compromise.

(Timothy A. Clary -- AFP/Getty)

"I don't think either one is going to have such a big electoral victory that they can say, 'Well there's a clear choice here, I've had such an overwhelming victory,'" David Walker, former Comptroller General and current deficit hawk, said at a Monday luncheon hosted by Bernstein Global Wealth Management.

If Obama wins, Steve McBee, president & CEO, McBee Strategic Consulting predicts that it will be by a narrow margin that will make him more likely to "play softball" and compromise on the Bush tax cuts and the rest of the fiscal cliff. Similarly, Walker believes that if Romney wins, he'll govern from the center-right and bring the rest of his party along with him. "He'd be head of the Republican Party," he said. "When the president is head of your party, you have a lot more ability to influence your caucus."

But political scientists are skeptical that the president's margin of victory will affect the way the Washington governs, whether the victory is big or small. Instead, they believe that the president's approach to governing will overwhelmingly depend on Congress — both in terms of the outcome of the Congressional races and how members of Congress view the incoming president. 

Members of Congress don't care about the president's margin. They care about their margins, and the role the president seems to have in them -- the so-called "coat tails" effect. "Our conclusion is that the down ticket races matter much more than the size of the president's victory (which is largely uncorrelated with how Congress reacts to the election)," says David Peterson, a political scientist at Iowa State University. "Members believe they owe their seats to the president they might be somewhat more likely to support him than if they don't," adds political scientist Jonathan Bernstein.

"When Reagan won in 1984, it was a landslide, but it didn't translate to big wins in Congress or governors mansions. The victory was believed to be about a combination of the economy and Reagan's personality, so members of Congress didn't need to react," Peterson explains. By contrast, unexpected victories and upsets in downballot races could usher in a more partisan agenda. Congress could end up taking a more moderate path, but it will depend far less on what the president's margin of victory is than their own. 

That said, Bernstein allows that a big, decisive victory could help the next president a little on its own. "The president's popularity, or at least perceptions of his popularity, probably matter," he says. If Obama wins the national vote by more than a point and/or more than 300 electoral votes, for instance, Democratic senators might be marginally more willing to play hardball.
But even in that scenario, the president's margin of victory only affects his ability to govern in as much as Congress itself sees it as affecting his ability to govern.