Via Mediaite, not the only case of a Republican hitting Paul hard today. Santorum’s been attacking him on his foreign policy, his age, and his track record on legislation, saying, “Show me one bill he’s passed in Congress. He’s been there 20 years.” The joke’s on you, Rick: He has passed one. Exactly one.

The clip’s worth watching not for Gingrich’s slightly outré admission that he wouldn’t support his party’s nominee over The One — Paul himself hasn’t even categorically ruled out a third-party bid, for cripes sake — but for the barrage of detail about Paul’s newsletters that he unloads in the first few seconds. He knew he was going to get this question so he used his answer time as a massive oppo dump for the benefit of people watching in Iowa who might have tuned out of the news over the past few days. Tough, tough stuff for a guy who’s sworn not to go negative. I wonder how long he rehearsed it. And I wonder what Romney would have said to the same question. The last thing he’d want to do right now is give Gingrich, Perry, or Santorum an opening by weakening Paul, and as the likely nominee, he has to be careful about alienating any of Paul’s supporters by going after him bareknuckle. Expect Mitt to play nice and gentle unless and until Paul starts to threaten him in New Hampshire.

Question: Is Gingrich really crossing the party by saying he wouldn’t vote for Paul as nominee when Paul’s support is being driven by non-Republicans?

In an analysis accompanying his most recent survey in Iowa, pollster Scott Rasmussen noted, “Romney leads, with Gingrich in second, among those who consider themselves Republicans. Paul has a wide lead among non-Republicans who are likely to participate in the caucus.”

The same is true in New Hampshire. A poll released Monday by the Boston Globe and the University of New Hampshire shows Paul leading among Democrats and independents who plan to vote in the January 10 primary. But among Republicans, Paul is a distant third — 33 points behind leader Mitt Romney.

In South Carolina, “Paul’s support is higher among those who usually don’t vote in GOP primary elections,” notes David Woodard, who runs the Palmetto Poll at Clemson University.

In a hotly-contested Republican race, it appears that only about half of Paul’s supporters are Republicans. In Iowa, according to Rasmussen, just 51 percent of Paul supporters consider themselves Republicans. In New Hampshire, the number is 56 percent, according to Andrew Smith, head of the University of New Hampshire poll.

At the Daily Beast, Peter Beinart predicts “the dominant storyline at the Republican convention will be figuring out how to appease Paul sufficiently to ensure that he doesn’t launch a third party bid. And in so doing, the GOP will legitimize its isolationist wing in a way it hasn’t since 9/11.” Really? What could they offer Paul to “appease” him? The obvious carrot is a speech in primetime at the convention, but they’d surely want him to endorse the nominee in return and it’s hard to imagine that happening. How is a guy who, in the words of his own son, has “always stayed true to his principles and convictions” supposed to lead a round of applause for mandate fans Mitt Romney or Newt Gingrich? He and Santorum are polar opposites on foreign policy and on gay rights so that endorsement’s not happening either. Maybe he’d consider endorsing Perry, but Perry’s probably a 50-1 shot right now so we don’t need to think too hard about it. The only alternative, I think, is to offer Rand Paul a primetime speech at the convention. He might be willing to endorse the nominee to prove he’s a party man ahead of his own presidential run down the line, and paying Ron Paul the respect of granting his heir apparent a national spotlight might deter him from running as an independent. That’s the only way out, I think. Any alternatives?