King, who had endorsed the GOP presidential frontrunner, abruptly switched horses and announced his support for Arizona Sen. John McCain.
In an interview, King cited Bush's decision to speak at Bob Jones University, a South Carolina institution that "is seen as anti-Catholic and anti-Black. It raised the whole specter of bigotry; that causes real fear among Jewish voters."
But the Bob Jones controversy was just the last straw, King said.
"Combine that with the fact that last year, Bush said he wasn't certain whether Jews could get into heaven," he said. "The fact Bush said that as part of an intellectual debate scared me -- and I'm not Jewish. If Jews can't get into heaven, who's next?"
And King said he was increasingly concerned about a campaign that seems to have lost its moorings.
"Bush is doing whatever he feels he has to do in any particular state," he said. "If the state after New Hampshire had been New York instead of South Carolina, you'd have seen a very moderate, open-minded George Bush. Rather than having a national message, he will take on the narrow, parochial views of whatever state he happens to be in at the time."
The Christian Coalition made an all-out effort for Bush in South Carolina; the campaign's shift in focus to the party's religious right-flank continued in Michigan, where the founder of the Christian right group, evangelist Pat Robertson, harshly attacked McCain.
South Carolina "will haunt the Bush campaign and the Republican party as it tries to win Jewish votes in November," said Marshall Wittman, an official with the Heritage Foundation and a top McCain supporter. "They allied themselves with the hard right, and that will have an impact on Jewish voters."
Wittman, who is Jewish, is Robertson's former legislative director. But this week he said he was shocked by the "nastiness" of the religious conservatives in the South Carolina race.
"I was appalled by what I heard my former comrades did in South Carolina," he said. "It has been very sobering for me. The allies of the Bush campaign really ran a gutter campaign."
When he was at the Christian Coalition, Wittman said, "There was a real effort to bring that constituency into the mainstream. But South Carolina was a huge setback."
Still, he said, the Jewish Republican leadership remains glued to Bush--"and that's something they'll have to deal with in November."
Wittman said there was at least a glimmer of good Jewish news for the GOP.
"Anecdotally, at least, it appeared McCain was attracting many Jewish Democrats who were considering voting for a Republican for the first time," he said. "That underscores the vulnerability of the Democratic Party in the Jewish community."
American University historian Allan J. Lichtman, who studies presidential politics, predicted that Bush will "steer way to the center, after the primaries. He'll probably come out with some strong policy statements on Israel in an effort to reassure the Jewish community."
Still, he said, the damage he caused to the GOP's Jewish outreach in South Carolina -- and the uncertainty Bush created when he declined to join McCain in urging columnist Pat Buchanan to leave the party last year -- will "keep his Jewish numbers very low. In the past two weeks, he hasn't helped himself with minority voters."
The South Carolina fallout could also impact congressional races.
Overall, Jewish voters will not play a huge role in the struggle for control of the House and Senate, but in key states--including New York, California, Florida and Illinois--the Jewish vote could prove important.
"It's a wonderful opportunity for the Democrats to exploit--but only if they play it properly, without exaggerating it," said Gilbert Kahn, a Kean University political scientist. "The onus will be on Republican candidates to delineate their differences with Bush on certain issues."
"There's a lot to suggest Jews are more inclined to be swing voters in congressional contests than at the presidential level," said a prominent Jewish Republican. "If Bush is the presidential nominee and if some of the concerns he generated in South Carolina persist, that could be a limiting factor, although it's way too early to make concrete predictions."