“If he were out of this race, we wouldn’t just be beating Mitt Romney, we’d be crushing him,” Hogan Gidley, a senior adviser to the Santorum campaign, said Wednesday. “We wouldn’t have won every state that Romney won, but we sure would have won a lot more of them.”…

“If he withdraws now he looks like a hero to conservatives, like a kingmaker,” Richard Viguerie, a long-established conservative activist, said. “As each day goes by he’s going to lose support.”…

Under the rules in many states, if the winning candidate in a given Congressional district secures only a plurality of its votes, then he must share the district’s delegates with the second-place finisher. Only by winning more than 50 percent of the vote can a candidate win the entire delegate slate. By Mr. Gingrich’s logic, Mr. Romney would be in a better position to take more delegates in the absence of Mr. Gingrich because he would have more room to secure a majority in a head-to-head race against Mr. Santorum.

But the Republican nominating process is approaching a new phase in which more states will award delegates through a winner-take-all method by Congressional district. After April 1, the only two states that will award delegates proportionally within Congressional districts are North Carolina and Kentucky.