Donald Trump Is Trying to Put His Rough Week Behind Him

U.S. Republican presidential candidate Donald Trump speaks at a campaign rally in West Allis, Wisconsin, United States, April 3. Reuters

Donald Trump is fighting to put a difficult week behind him and finish strong on Tuesday in Wisconsin, a state whose primary contest may prove to be a turning point in the race for the Republican presidential nomination.

The Republican front-runner is at risk of losing the Midwestern state to U.S. Senator Ted Cruz of Texas, an outcome that would dent the New York billionaire's aura of inevitability and make it harder for him to win the 1,237 delegates needed for the party's nomination for the Nov. 8 election.

On the Democratic side, U.S. Senator Bernie Sanders of Vermont is trying protect his lead over front-runner Hillary Clinton in the opinion polls in Wisconsin and eke out another victory over the former secretary of state.

Trailing Cruz in the polls in Wisconsin, Trump on Sunday night told supporters in West Allis,Wisconsin, that Cruz was a liar and a "dirty rotten cheater" who is weak on immigration and would cut Social Security benefits.

"Wisconsin is going to be such a big surprise on Tuesday. We are doing so well," Trump said.

A loss would add to Trump's woes after his campaign was rocked last week by the fallout from his suggestion, which he later dialed back, that women be punished for getting abortions if the procedure is banned.

He also drew fire for comments that he would not rule out using nuclear weapons in Europe and that Japan and South Korea might need nuclear weapons to ease the U.S. financial commitment to their security.

"Was this my best week? I guess not," Trump told "Fox News Sunday" in an interview conducted Friday. But, he added: "I think I'm doing OK."

Cruz, speaking to supporters on Sunday in Green Bay, Wisconsin, was eager to capitalize onTrump's potential missteps.

More Republicans are recognizing, said Cruz, that "nominating Donald Trump would be a train wreck."

Cruz faces difficulty in winning the delegates needed to secure the nomination, given that the next states to vote, including New York on April 19, are Trump-friendly territory.

Clinton is already eyeing New York, holding campaign stops there on Monday even as other candidates make their final pitches in Wisconsin.

"I'm absolutely confident I will be the nominee," Clinton told ABC in an interview that aired Monday as she and Sanders continued to spar over scheduling more debates.

Sanders adviser Tad Devine said the Vermont Senator wanted another prime-time debate with Clinton.

"If we can continue to win, if he has a good day tomorrow, we're going to make his case through New York all the way to California," he told CNN.

Republicans Cruz and Ohio Governor John Kasich, third in the race, want to deny Trumpenough delegates so that the nominee is determined at the Republican National Convention in July.

Over the weekend, Trump complained Kasich was an irritant gobbling up some of the delegates Trump needs.

"The problem is he's in the way of me, not Cruz," Trump said.

Kasich, who has vowed to stay in the race, tweeted: "That's not how our republic works, Donald. We'll keep fighting until someone reaches a majority of delegates."

On Monday, RNC strategist Sean Spicer said the party would "never tell any candidate to get in or out of the race."

"The party is simply the arbiter, the people who put on the show to ensure that these delegates have a system to vote," he told CNN.