NEW YORK (Reuters) - For lifelong Republican Joe Errigo, deciding to cross party lines and support a liberal Democrat for New York governor wasn’t nearly as difficult as one might expect.

A supporter holds out a postcard at a Tea Party Express rally where former Alaska Governor and 2008 Republican vice presidential nominee Sarah Palin spoke, on Boston Commons in Boston, Massachusetts April 14, 2010. REUTERS/Brian Snyder

Republican candidate Carl Paladino -- backed by the conservative Tea Party movement -- raised such political hackles he spawned a “Republicans for Cuomo” movement supporting Democrat Andrew Cuomo.

Similar groups can be found in heated races elsewhere nationwide, often those featuring Tea Party-endorsed candidates, attacked by Democrats and some moderate Republicans as extreme.

“When I saw his website, I said nobody could be that dumb,” said Errigo, an upstate New York Assemblyman, of Paladino, a Buffalo developer and political newcomer.

“He has alienated every group that I could think of,” said Errigo. “He should write a book on how to lose an election.”

In Delaware, where Christine O’Donnell has Tea Party support, Republicans backing Democrat Chris Coons include a former state judge and former U.S. Congressman. A “Republicans for Coons” Facebook site reads: “Because we just can’t support Christine O’Donnell.”

In Arizona, “Republicans for Giffords” are backing Democratic Rep. Gabrielle Giffords over conservative Iraq War veteran Jesse Kelly.

In Nevada, incumbent Democrat Sen. Harry Reid, who faces Tea Party favorite Sharron Angle, counts among his Republican supporters an array of influential gaming and casino executives.

“Mainstream Republicans are refusing to support the latest crop of insurgent candidates in the Republican Party because of their extremist beliefs,” said Deirdre Murphy, spokeswoman for the Democratic Senatorial Campaign Committee in Washington.

“A TREMENDOUS OPPORTUNITY FOR REPUBLICANS”

In New York, Paladino has riled fellow Republicans, from his view that average Americans cannot understand adjustable mortgages, his spat with a reporter that went viral on the Web, to his plan to “take a baseball bat” to the state capital.

“This was a tremendous opportunity for the Republicans this year,” said Onandaga County, New York, Executive Joanie Mahoney, a Republican whose support for Cuomo marks the first time she has supported a Democrat.

“But we can’t just have fighting and rhetoric,” she said. “I just didn’t have the sense, knowing what I know about state government, that sending somebody there with a baseball bat was going to move the ball forward.”

Other names in “Republicans for Cuomo” are former state party chairman J. Patrick Barrett and hedge fund manager Anthony Scaramucci, who handled finances for Republican Rick Lazio, who was defeated by Paladino in the primary.

Plenty of Republicans are supporting Cuomo but keeping quiet, said Mahoney.

“I have had people tell me things privately that I don’t think they’re willing to say publicly,” she said.

The latest poll, released on Wednesday, showed Cuomo with a 20-point lead over Paladino, with 7 percent undecided.

Mahoney earned criticism from state Republican Chairman Ed Cox, who called her endorsement of Cuomo a “shallow act” that showed “poor judgment.”

“It was a very difficult decision personally,” she said. “I knew I would take some heat from my party which I have.”

What came as more of a surprise, she said, was the number of Republicans who got in touch to say: “We know why you did it, and we’re with you.”