What would a Mitt Romney...

...presidency really look like? How would it be different from President Obama's? Would a President Romney be any better at dealing with Congress? Would he be the master of the tea party, or its servant?

The Washington Monthly has a new series, "What if Obama Loses?," that attempts to answer those questions and more.

In "Congress," Thomas Mann and Norman Ornstein first assume a Republican Congress (my emphasis):

A President Romney would be in a poor position upon taking office to change the course outlined in his campaign. He is already suspected as an infidel by many Republican activists. His fiscal policy would almost certainly be ambitious, one not unlike the budget resolution written by Representative Paul Ryan and passed by House Republicans. Indeed, this is the course Romney has taken with his professed economic plan, released in early November. If Romney tried to dilute his own proposal, he would be met at the beginning of his presidency with a full-scale revolt on his hands from his own party, both in and out of Congress.

And if the Republicans don't control Congress?

Of course, there is another possibility with a Romney presidential victory: continued divided government, either because disgruntled voters throw Republicans out of their majority in the House or because they do not give Republicans the necessary three-seat gain to win a majority in the Senate. Would Romney be able to navigate through to bipartisan compromises here? For instance, could he, as a Republican president, do what Barack Obama has been unable to do: convince a significant number of Republican lawmakers to accept tax increases or defense cuts as part of a deficit-reduction plan? We are dubious. Any attempt to find common ground with Nancy Pelosi and House Democrats or Harry Reid and Senate Democrats would be met with staunch resistance by the conservatives who dominate the Republican ranks in Congress and who do not trust Romney to begin with. Alternatively, if Romney were to sign legislation passed by a Democratic Congress without significant GOP votes, he would be directly thumbing his nose at his own party’s far-right base, which holds sway over 95 percent of the Republicans in the House and at least 85 percent in the Senate. There is little in his background or current run for the nomination that suggests he has that kind of courage.