INDIANAPOLIS (CBSNewYork/AP) -- As the voters take to the polls Tuesday in the crucial Indiana primary, the back-and-forth between Ted Cruz and Donald Trump has hit a fever pitch.
As CBS2's Dick Brennan reported, the new allegations by Trump has many scratching their heads, and has Ted Cruz in a fury.
The day began with accusations Trump made about Ted Cruz's father Rafael Cruz. Trump said that Rafael Cruz was acquainted with John F. Kennedy's assassin, Lee Harvey Oswald.
"His father was with Lee Harvey Oswald prior to Oswald's being, you know, shot. I mean, the whole thing is ridiculous," Trump told Fox & Friends.
The GOP front-runner was referring to a recent National Enquirer report that claimed that the elder Cruz appeared in a 1963 photo of Oswald as he handed out leaflets for the Fair Play for Cuba Committee.
Cruz called Trump's claims "kooky'' and "nuts."
"While I'm at it, I guess I should go ahead and admit, yes, my dad killed JFK, he is secretly Elvis, and Jimmy Hoffa is buried in his back yard," Cruz said.
"I'm going to tell you what I really think of Donald Trump," Cruz added. "This man is a pathological liar. He doesn't know the difference between truth and lies."
The allegation triggered a long rant by Cruz on all things Trump.
"Bullies come from a deep yawning cavern of insecurity, there's a reason Donald builds buildings and puts his name on them," Cruz said.
"He will betray you on every issue," Cruz continued.
"Donald is terrified by strong women. He lashes out at them," he added,"Donald Trump is a serial philanderer, and he boasts about it...Donald Trump is such a narcissist that Barack Obama looks at him and goes 'dude what's your problem?"
Trump responded in a statement.
"I have watched Lyin' Ted Cruz become more and more unhinged. Ted Cruz does not have the temperament to be President of the United States," Trump said.
Indiana is a high-stakes test for Cruz's slumping presidential campaign. It's one of the last opportunities for the Texas senator to halt Trump's stunning march toward the GOP nomination.
With 57 delegates at stake, Cruz has spent the past week camped out in Indiana, securing the support of the state's governor and announcing retired technology executive Carly Fiorina as his running mate.
But in the latest polls, Trump has a 15-point lead over Cruz heading into Tuesday's contest.
"It's pretty much over if Donald Trump wins, especially if he wins by the margins the polls are suggesting," said John Heilman, Bloomberg Politics co-managing editor.
While Trump cannot clinch the nomination with a big win in Indiana, his path would get easier and he would have more room for error in the campaign's final contests.
In a blistering attack on his rival, Cruz said that if Indiana lets Trump win Tuesday America is "looking, potentially, at the Biff Tannen'' presidency, a reference to the 1980s film "Back to the Future.''
"We are not a proud, boastful, self-centered, mean spirited, hateful, bullying nation,'' Cruz told reporters in Evansville, Indiana, before citing the film "Back to the Future II.'' The film's screenwriter said in an interview with The Daily Beast last year that the film's character Biff Tannen was based on Trump.
"The screenwriter says that he based the character Biff Tannen on Donald Trump -- a character of a braggadocios, arrogant buffoon who builds giant casinos with giant pictures of him everywhere he looks,'' Cruz said. "We are looking, potentially, at the Biff Tannen presidency.''
On the Democratic side, Bernie Sanders is acknowledging that it'll be a big challenge to amass enough delegates to catch up with front-runner Hillary Clinton.
He said that with 10 states left, his campaign needs to earn more than 50 percent of the remaining delegates up for grabs.
Clinton also had to apologize to a coal miner after a comment she made saying she would put coal miners out of business.
"What I said is that it's going to happen unless we take action to help prevent it. I made one misstatement, and I apologize for that. It was not meant to be taken the way it was taken at all," she said.
Sanders had coffee with voters in Indianapolis Tuesday while Clinton campaigned in West Virginia ahead of that state's primary next week.
Clinton has a four-point lead over Sanders in the latest poll of Indiana, but that is within the polls margin of error.
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