Just about every name Republican at this point has endorsed Mitt Romney. He is, after all, the only guy in the race who can and will win his party’s nomination. So Senate Majority Leader Mitch McConnell (R-Ky.) and House Speaker John Boehner (R-Ohio) both gave their stamp of approval on Tuesday.

But there is a holdout among household-name Republicans: Rick Santorum. I know, the tension is too much to bear: When, oh when, will he announce he is throwing the legion of his supporters to the man whom 90 percent of Republicans already support? He’s still in self-delusion land, it seems. The National Journal reports:

To crystallize the point that he isn’t going to make an endorsement in the immediate future, Santorum told his supporters that it was entirely up to them whom to vote for in next week’s Pennsylvania primary. “I haven’t supported any candidate at this point,” he said.

He said he’s working on some structure to house the conservative movement. (I think it’s called the Republican Party.) He proclaimed:

He said he was working through ideas for a “structure to promote these ideas” and promised an announcement in the next week or two. As for delegates, those may not be released even if he does back another GOP candidate.

“We still have delegates, many of them committed, and we want to make sure that our delegates get a chance to go to the convention and have a say,” Santorum said.

Whatever. I don’t think the Romney team cares. Conservative voters who have rallied around Romney sure don’t care.

It is very hard to give up the limelight. But Santorum is headed back to obscurity. If Romney wins the White House, he owes Santorum nothing and won’t be obliged to give him a job. If Romney doesn’t win, there are many super-star candidates who appeal to mainstream Republicans, donors, party insiders and the grass-roots — e.g., New Jersey Gov. Chris Christie, Virginia Gov. Bob McDonnell, Sen. Marco Rubio (R-Fla.), Jeb Bush, Sen. Kelly Ayotte (R-N.H.), Rep. Paul Ryan (R-Wis.) — who have been good Republicans and constructive players throughout the process. They all have their “structure” (the word is PAC) and have the proven ability to raise money and bolster candidates. (For example, Rubio is pitching in to help Josh Mandel, an Ohio candidate for the U.S. Senate.)

Santorum’s problems will remain — his lack of appeal beyond a narrow ideological band and the smallness of his character. This latest example is par for the course and won’t help him with either liability.