This is the fourth national poll in the past week to show him surging but the very first to have him in the lead. Amazing.

The poll shows Cain, who stood at just five percent support two weeks ago, now holding 17 percent support among Republican primary voters. That puts the former Godfather’s Pizza CEO into a tie with Romney, the former Massachusetts governor, whose support has essentially held steady over the past two weeks.

Perry, meanwhile, has dropped from 23 percent support to just 12 percent support over the past two weeks, a sign that the Texas governor’s shaky debate performances – in which he has alienated portions of both the Republican base and the party establishment – have taken their toll…

The CBS News poll shows Cain as the top choice among self-described conservatives, with 21 percent support. (Two weeks ago, he polled at just six percent with this group.) Romney polls in second among conservatives with 15 percent support, followed by Perry at 13 percent. Cain is also the top choice of Republican primary voters who support the Tea Party, polling at 24 percent to Romney’s 17 percent, Gingrich’s 13 percent and Perry’s 12 percent…

There is not a groundswell for the most prominent Republican still openly considering a run, 2008 vice presidential nominee Sarah Palin, to jump in: Three in four Republican primary voters said they would not like to see her enter the race. Just 23 percent said they wanted to see a Palin candidacy.

Just 10 percent of Republican primary voters say they agree with Perry that children of illegals should be eligible for in-state tuition. Serious question: Has any Republican gone on to win the nomination by following Perry’s path here, jumping in late to great white-knight acclaim and then dropping precipitously in the polls after a series of disappointing early stumbles? Has anyone recovered from that dynamic or is the end result always a Fred-Thompson-esque sputter? I don’t think Team Perry would mind the new numbers if it were a simple matter of Perry falling back in the pack with Romney stuck at 20-25 percent, but they must be a bit worried that some conservatives are switching to Cain instead of reverting to the “don’t know” column. It’s easy to win people back who are undecided but it’ll take work to convince them after they’ve switched allegiances. Especially since, unlike Perry, Cain seems to be getting better as a candidate.

As for Romney, Cain has two big problems. The first is that 32 percent of those polled by CBS say Romney is most likely to beat Obama compared to just eight percent who say the same of Cain. (16 percent say Perry.) The second is, well, this:

With Governor Chris Christie confirming today that he won’t seek the presidency, some big-name donors are finally ready to commit themselves to Mitt Romney.

“A lot of us who normally would have been in this presidential race a long time ago, have been waiting for Christie to make a decision,” said Georgette Mosbacher, a Republican uber-fund-raiser and finance co-chair of the Republican National Committee who was among a group of Republican bundlers hoping to convince Christie to enter the race. “I think tomorrow, we’ll be contacting one another and probably put something together with Romney.”

“I’m going to go with Mitt Romney,” said John Catsimatidis, another donor who had been intrigued with Christie, in a brief phone interview this afternoon…

Mosbacher said the big bundlers in her circle “do not consider a Perry factor.”

Ken Langone, the billionaire who founded Home Depot and was pushing Christie hard to jump in, also said today that he’ll back Romney. Big question: Given the dynamics of the race, who should Perry attack now — Romney or Cain? He can’t afford to have Cain hang around the top tier or else the conservative vote will split, but if he attacks the most popular underdog in the race, he risks an even greater backlash. Ironically, I think his best bet now is to stay focused on Romney but push an electability argument of his own: Namely, that Cain simply doesn’t have the resources to compete with Romney over the long haul, so if you want to stop Mitt, there’s only one game in town. Sad that Perry might be reduced to selling himself asessentially the “Not Romney” in the race, but if it works, oh well.