(Josh Roberts, Reuters)

Public Policy Polling (PDF) (4/4-7, Republican primary voters, no trendlines):

Donald Trump (R): 26

Mike Huckabee (R): 17

Mitt Romney (R): 15

Newt Gingrich (R): 11

Sarah Palin (R): 8

Ron Paul (R): 5

Michele Bachmann (R): 4

Tim Pawlenty (R): 4

Someone else/Undecided: 10

(MoE: ±4.9%)

It's an embarrassing time to be a Republican—well, more embarrassing than usual. An abrasive reality-show host and real-estate "faux-gul" with one of the worst comb-overs in American history is now soaring to the top of the GOP's contender list, and it's all for one reason: the "b" word. Trump's fetish for just about every wild birther conspiracy theory might make supposedly civilized beltway Republicans (if there even is such a thing) wince with chagrin, but it's rather endeared him to the party's base.

So maybe you're saying, Trump won't run—this is just a stunt, none of this is going to matter. I disagree. First off, every day that birtherism is in the news just makes the Republican Party look more ridiculous, fires up Democratic partisans, and alienates independents. Republican leaders know this, with Karl Rove going so far as to blame Obama himself for propagating this mind-virus. If The Donald is simply the host organism, then it's a role he should understand well, since he's spent his whole life as a parasite.

But there's another, deeper problem for the Republicans which pollster Tom Jensen identifies. Tom says that if Trump doesn't run, there will be a vacuum to fill:

[S]omeone who taps into the same sort of hard, hard right sentiment he's appealing to right now will get their votes—it's hard to imagine these folks voting for a more centrist candidate like Romney or Pawlenty. And that means there's a very serious contingent within the Republican Party that's less concerned with beating Barack Obama than having a nominee who gets them fired up. That suggests many GOP voters have not learned the lessons of Nevada and Delaware and that Obama may survive despite his weak approval numbers because the Republicans end up defeating themselves.

This isn't idle speculation. Tom included another clever question with this poll which shows just how diseased the Republican base really is:

Q: Would you be willing or unwilling to support a candidate for the Republican Presidential nomination who firmly stated they believed Barack Obama was born in the United States? Willing to support non-birther: 38

Unwilling to: 23

Unsure: 39

A quarter of the GOP electorate simply won't support a candidate who is not a birther, and two-fifths aren't sure. If they can't vote for Trump, these people will need to go somewhere. They could gravitate to Michele Bachmann, they could inspire another candidate go full-birther to suck up their votes, or they could stay home. Whatever happens, every outcome only hurts the Republican Party. I never, ever thought I'd say something like this, but ya know, we really should be grateful to Donald Trump.