By Ginger Gibson and Andy Sullivan
WASHINGTON (Reuters) - Republicans desperate to stop Donald Trump from capturing the party's presidential nomination may have to unite behind Ted Cruz, a polarizing figure who has made many enemies within the party.
Cruz, 45, a senator from Texas, won nominating contests in Kansas and Maine on Saturday, bolstering his argument that he is the leading alternative to Trump, 69, the blunt-spoken billionaire businessman.
Many mainstream Republicans are reluctant, however, to rally behind Cruz, whom they see as too conservative for the general electorate in the Nov. 8 election to succeed Democratic President Barack Obama.
Cruz has run as an outsider bent on shaking up the Republican establishment in Washington. A favorite of evangelicals, he has called for the United States to "carpet bomb" the Islamic State militant group and has pledged to eliminate the tax-collecting Internal Revenue Service and four Cabinet agencies.
But he angered many Republican colleagues when he led an unsuccessful effort to repeal President Barack Obama's Affordable Care Act that shut down the government for 16 days in 2013.
Republican pollster Neil Newhouse said Cruz had not yet shown an ability to appeal beyond the most conservative voters.
"The way things are going, I think it's extraordinarily unlikely that Senator Cruz becomes the focal point for Republicans who want to stop Trump," said Newhouse, who was lead pollster for 2012 Republican presidential nominee Mitt Romney.
Kim Reem, a member of the executive committee of the National Federation of Republican Women, said three factions were emerging among Republicans: those supporting Trump, those backing Cruz, and supporters of the party establishment. None are inclined to compromise, she said.
"I don’t see a path to making everybody happy," she said.
Former U.S. Senator Trent Lott of Mississippi said he would have a hard time supporting a Cruz nomination. "He'd have to change his tactics and his conduct an awful lot," he said.
Cruz has feuded with party leadership, including Republican Senate Majority Leader Mitch McConnell, and has often accused fellow Republicans of selling out conservative principles.
Although he has been in the Senate for four years, Cruz has not won a single endorsement from any other senator. He touts that on the campaign trail as evidence he is an outsider.
RUBIO FLORIDA HOPE
To win the nomination, 1,237 delegates are needed. According to The New York Times, Trump leads with 384 delegates and Cruz has won 300. U.S. Senator Marco Rubio, 44, of Florida, an establishment favorite still seen by some in the party as an option to Trump, has won 151 delegates and Ohio Governor John Kasich trails with 37.
Some establishment Republicans say the best way to stop Trump would be for Rubio to win the 99-delegate Florida contest and Kasich the 66-delegate Ohio primary. Opinion polls show Cruz trailing in both states, which award all their delegates to the top vote-getter on March 15.
Michigan, Mississippi, Idaho and Hawaii hold nominating contests on Tuesday. Recent opinion polls show Trump leading by a wide margin in Michigan, the day's biggest prize.
At a rally in North Carolina, Trump said he would do well in those contests because he supported important local industries.
"Michigan's gonna be, look, I've been fighting hard for cars," he said. "We have Idaho, we love Idaho potatoes, right?"
If Cruz, Rubio and Kasich can collectively prevent Trump from getting the needed majority of delegates, they could force a brokered Republican Party convention in July in Cleveland, aimed at producing a compromise candidate.
Even if Cruz gets the second-highest vote total, he may have trouble claiming the nomination at the convention over Trump.
If nothing else, the debate reveals deep divisions within the party.
Slater Bayliss, a Florida Republican who raised money for former Florida Governor Jeb Bush before he dropped out of the race, said: "From my perspective, Senator Cruz's views are indicative of only a very small cohort in our party."
Republican donors, unhappy with Trump policies like his calls to deport 11 million illegal immigrants and temporarily bar all Muslims from entering the United States have poured millions of dollars into attack ads over the past week.
The Club for Growth, an advocacy group that pushes for lower taxes and spending, said on Monday it would spend $2 million on TV ads questioning Trump's conservative credentials in Illinois, one of six states or territories that holds a nominating contest on March 15.
Outside groups have spent more than $10 million on anti-Trump advertising in Florida and $23 million in other states, according to federal records.
Trump criticized rivals for running what he described as false advertising. "By the time you get them to admit that it was wrong, the election's over," he said.
(Additional reporting by Megan Cassella, Luciana Lopez and Grant Smith; Editing by Alistair Bell)