There are still plenty of question marks surrounding the Republican presidential contest after Super Tuesday. That’s especially true on Capitol Hill, where Ed O’Keefe reports many lawmakers still resist getting behind a candidate.

The tumultuous nature of Super Tuesday’s primaries made it impossible for Mitt Romney to quickly seal up the Republican presidential nomination and likely delayed his hopes of consolidating support on Capitol Hill.

Need an example? Sen. Lindsey Graham (R-S.C.) said Tuesday that Romney victories in Ohio and Tennessee would mean “he’s got a good case to make that it’s over.”

Romney won Ohio — barely — and lost in the Volunteer State, meaning Graham and others are nonplussed.

As he holds a lead in delegates, Romney also has the most support among GOP lawmakers. He has at least 16 senators and 67 House lawmakers in his camp; Newt Gingrich trails with the support of 11 former House colleagues; Rick Santorum has four House lawmakers; and Rep. Ron Paul (R-Texas) has his son, Sen. Rand Paul (R-Ky.)and two other House lawmakers backing him, according to a tally maintained by Roll Call.

But Sen. Richard Burr (R-N.C.), another Romney backer, said a less-than convincing result Tuesday night would make it difficult for his undecided colleagues to jump in.

“When Romney’s running only against the president and not against [Gingrich and Santorum], it’ll be a good sign,” he said Tuesday.

Although the field continues to split state victories, Romney’s lead in the delegate count is already wide, and his rivals’ chances of overcoming it are slim, writes Karen Tumulty:

The GOP nomination contest was designed to play out more slowly than in the past. Through the end of this month, states are required to allocate their delegates in proportion to the votes each candidate receives. That means just about everyone comes away from just about every contest with something to show for it — and a rationale for continuing to the next one.

And while the emptying of a campaign’s bank account used to spell the end for a candidate, Rick Santorum and Newt Gingrich have been kept on life support by billionaire supporters who have taken advantage of changes in campaign law to pour millions into independent super PACs that support the candidates.

At the same time, party leaders and rank-and-file Republicans are increasingly anxious to bring the process to a conclusion, to spare their eventual nominee further attacks from within the party fold. It is becoming more apparent that a lengthy primary battle could have a corrosive effect on the GOP’s prospects in the fall against a Democratic incumbent whom most Republicans are desperate to defeat.

“The next couple of weeks will be dominated by different groups of people accepting reality, which is that Mitt Romney will be the nominee,” predicted Steve Schmidt, a political strategist who ran day-to-day operations for GOP nominee John McCain in 2008. “There’s just not going to be much appetite in the Republican Party for a long, drawn-out primary when the outcome is clear.”

Going into Tuesday’s balloting, Romney had just over 200 delegates, according to Associated Press estimates — well short of what he needs to secure the nomination but more than twice as many as Santorum, who was running second at just over 90 delegates. Gingrich and Rep. Ron Paul (Tex.) were far behind.

Even if one of them were to begin performing far better than he has to date, it is difficult to see how he could make up the gap.

“Delegate-wise, it’s virtually impossible for Rick Santorum or Newt Gingrich to get to 1,144,” said Josh Putnam, a Davidson College professor who is an expert on the quirky rules by which Republicans in various states apportion their convention delegates.

Yet even Paul, who has conceded publicly that his “chances are slim,” plans to forge on.

The candidates’ rationales for staying in vary, and there are good reasons for each to continue to contend for the nomination. Chris Cillizza explains why Newt Gingrich should not drop out yet:

Gingrich, not surprisingly, is having none of the dropout talk — insisting that he would drop out of the race if he thought Santorum could beat Romney and then best Obama. Except, he doesn’t. “I think each of the three candidates has strengths and weaknesses and that this is a very healthy vetting process,” added Gingrich.

Gingrich is right. He shouldn’t drop out of the race. At least not yet. Here’s why.

A quick look at the calendar for the rest of March tells the story. The marquee contests next Tuesday are in the South when Alabama and Mississippi are set to vote. (Hawaii also votes that day.) Louisiana holds it caucuses on March 24.

Gingrich has already made clear today that he will focus all of his time and resources over the next few weeks in the South, skipping the Kansas caucuses — set for this Saturday — in the process. “Everything between Spartanburg all the way to Texas, those all need to go for Gingrich,” said campaign spokesman R.C. Hammond.

If Gingrich can win in Alabama, Mississippi and Louisiana — and, to be clear, that’s a big “if” — he will have stockpiled enough delegates in the most reliably Republican region in the country to give himself a bit of bargaining power with the eventual nominee.

So, let’s think about this from Gingrich’s perspective for a minute. If he drops out now, he is playing kingmaker to Santorum who, according to the hard facts of former Massachusetts governor Mitt Romney’s delegate advantage, is unlikely to wind up as the nominee.

If he holds out and can score wins in the deep South over the next three weeks — not entirely out of the question — then Gingrich is in a position to cut a deal with Romney who will be looking for ways to consolidate support and close out the nomination by then.

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