But in back-and-forth emails, Protestant fundamentalist leaders who attended – most of them backing former House Speaker Newt Gingrich to be the anti-Romney candidate — are accusing Catholic participants of conniving to rig the vote.

They said they were conned into leaving after the second ballot on Saturday. They said pro-Santorum participants held a third ballot which Mr. Santorum won with more than 70 percent of the vote — far higher than the nine-vote margin he won on the first ballot.

“My view is that the vote was manipulated,” said a prominent social conservative who asked not to be named.

Now, a prominent evangelical political organizer is saying to others confidentially he has evidence that in a least one instance a participant was seen writing Mr. Santorum’s name on four separate ballots and putting them in the ballot box.