CLIVE, Iowa - Ted Cruz on Wednesday ratcheted up his criticism of GOP presidential rival Donald Trump, belittling the celebrity real estate mogul as a "fragile soul" for refusing to participate in Thursday's debate and likening him to an "imperial dictator."

Cruz, a first-term senator from Texas, and Trump are locked in a dead heat before the Iowa caucuses begin the presidential nominating contest on Monday.

The two candidates in recent weeks have dropped all pretense of the mutual non-aggression pact they once held as outsiders attacking the Washington establishment.

On Wednesday, Cruz, joined by high-profile conservatives such as the Family Research Council's Tony Perkins, went after Trump in perhaps his harshest terms yet.

"Listen, Donald Trump's position on health care is that he supports Bernie Sanders-style socialized medicine for everyone," Cruz told a couple hundred supporters at an event venue here, just west of Des Moines.

"He doesn't think Obamacare goes far enough: He wants to expand it, so that we have Hillarycare, then Obamacare, and Trumpcare is socialized medicine for every American," Cruz said.

He added, to laughter and applause, "Donald is entitled to have that view. You might even call that view a New York value."

"Both he and Bernie Sanders are native New Yorkers," Cruz said, referring to the Vermont senator who's challenging Hillary Clinton for the Democratic nomination.

(Trump says he opposes the Affordable Care Act. In the past, he has said he supports universal health care.)

By contrast, Cruz said, "If I'm elected president, we will repeal every word of Obamacare."

Most striking about Cruz's speech at the "pro-life" campaign rally: It was nearly identical to the stump speech he gave at a half-dozen events the day before, except on Tuesday, he rarely mentioned Trump by name.

For his part, Trump has questioned Cruz's eligibility to be president, given that the senator was born in Canada. Trump also describes Cruz as "weak" on immigration.

The sparring comes as the candidates compete for the influential evangelical vote in Iowa.

Offering a litmus test by which to judge the candidates, Cruz told the audience to consider how he and his rivals had acted with regard to gun rights, immigration, gay marriage, and Iran.

Cruz noted that Trump once said in an interview that he was "pro-choice" and suggested he supported partial-birth abortions. The senator noted that Trump had accepted gay marriage as the law of the land, because of a Supreme Court decision last June.

"Those are word-for-word the talking points of Barack Obama," Cruz said.

"That decision is fundamentally illegitimate," he said, adding, "it will not stand."

And he said Trump might try to secure a "better deal" with Iran over its nuclear deal with the United States and other world powers, arguing that any accord with that country was naive.

Cruz also taunted Trump for saying he wouldn't participate in Thursday's debate, to be broadcast by Fox News. Trump objected to Fox's decision to let journalist Megyn Kelly moderate the debate. The businessman has said he was treated unfairly by Kelly in an earlier debate.

"Apparently Mr. Trump considers Megyn Kelly very, very scary," Cruz said.

On Tuesday, Cruz proposed a one-on-one debate with Trump, and speaking here Wednesday announced he had reserved a place and time (Saturday, 8 p.m. in Sioux City) for the hypothetical event.

After suggesting a conservative like Fox News personality Sean Hannity could moderate the debate, Cruz told the audience: "He's afraid of you ... His record doesn't match what he's selling."

Trump took to Twitter to attack his opponent Wednesday.

"Even though I beat him in the first six debates, especially the last one, Ted Cruz wants to debate me again," Trump wrote. "Can we do it in Canada?"

856-779-3846 @AndrewSeidman