MIAMI, March 10 (UPI) -- The Republican candidates conducted Thursday's debate in Florida with a much more muted and substantive tone, debating trade, immigration policy and foreign affairs while avoiding the personal attacks that have defined their prior meetings.
In a contrast with their meeting in Detroit last week where the opening minutes saw front-runner Donald Trump referencing the size of his manhood in response to attacks made on him previously, the candidates this time were queried on their positions relevant to free trade agreements and guest worker visas.
Trump acknowledged his business empire's reliance on the visas that have proven unpopular among many Republicans, saying the rules as they're written now make it legal and more advantageous to bring in workers from other countries than it is to hire Americans.
"It's important to say I'm a businessman and I have to do what I have to do," Trump said. "It's unfair for our workers."
Sen. Marco Rubio also had to face an awkward fact about his position on immigration -- his proposal to overhaul the system would have prevented his own parents from coming here before he was born.
"The problem is, nothing works like it did 60 years ago," Rubio said. "The 21st century economy is not creating nearly enough jobs for people who don't have skills."
Instead, he said immigrants should be forced to answer a simple question before being granted admission: "What job are you going to be able to do when you get to the United States?"
Ohio Gov. John Kasich was pressed on his support for free trade deals critics say have led to many industrial jobs being moved overseas.
"My position has always been we want to have free trade, but fair trade," Kasich said. "It is absolutely critical when another country breaks those agreements ... when countries cheat, we need to blow the whistle. We don't want to lock the doors, pull down the blinds and leave the world."
After the turn through domestic policy, the candidates were asked about foreign affairs, including how best to defeat the Islamic State. Asked whether they would support an Army general's estimation it would take between 20,000 and 30,000 ground troops to do so, Trump was the lone candidate to say explicitly he would do so.
Kasich said he would work to rally allies in the Middle East to join the fight.
"The fact is, a lot of these Muslim countries can't believe what they see out of people who have distorted their faith," Kasich said.
Trump was asked whether he stands by his remarks that Muslims hate America and he largely doubled down, saying "a lot of them" do.
Rubio, who is the child of Cuban immigrants, launched a broadside attack against re-establishing diplomatic ties with the communist island. Trump expressed concern about making a "good deal" to reopen ties there and whether Cuba would "sue" the United States for economic reparations as a result of the embargo.
Rubio shot back: "I don't know where they're going to sue us, but if they sue us in a court in Miami, they're going to lose."
Rubio went on to rattle off a list of things he would require Cuba's government to do before ending the embargo, including holding free elections and returning Americans who have fled there to avoid criminal prosecution.
Rubio's speech drew the loudest sustained applause from the audience of the night.
Trump was also asked about the tenor -- and increasing violence -- at his campaign rallies, including an incident earlier Thursday when a white man punched a black protester in the face. The debate's moderator, Jake Tapper of CNN, reminded Trump of numerous remarks he's made suggesting his supporters use violence against protesters who turn up at his raucous rallies.
"We have 25-30,000 people. When they see what's going on in this country, they have anger. ... There's also a great love for the country. But I certainly don't condone that at all," Trump said. "We have some protesters who are bad dudes, who are doing bad things."
Cruz turned his rebuttal back around on Trump criticizing what some have called "loyalty oaths" he asks his supporters to take during rallies.
"At Donald's rallies recently he's taken to asking people in the crowd to raise their hand and pledge their support to him. I've got to say, to me that's exactly backwards. This is a job interview. We're here pledging our support to [voters], not the other way around," Cruz said.
The four Republicans remaining in the race for their party's presidential nomination met for the 13th time in their campaign and the second time in a week, this time ahead of Florida's crucial winner-take-all primary on Tuesday.
The men were last on a debate stage a week ago in Detroit, when the caustic insults that have defined the campaign dominated the discussion.
In that debate, Trump responded to a criticism from Rubio about his "small hands" by referring to the size of his own manhood -- a remark many regarded as a new low in the campaign.
Later, Rubio said he regretted his behavior leading up to the debate.
"If that's what it takes to become president of the United States, then I don't want to be president," Rubio said during a town hall meeting broadcast on MSNBC. "I don't think that's what it takes to be president. I know it's not what it takes, it's not what we want from our next president, and if I had to do it again I would have done that part differently."
All eyes were on Rubio in Florida, his home state -- where polls show him trailing Trump badly.
Trump and Cruz, who is running second in the delegate count, have each called on Rubio to exit the race amid his disappointing finishes.
The fourth candidate, Kasich, faces a similar problem entering Thursday's debate. He, too, has failed to win many delegates and also faces a Tuesday primary on his home turf -- though some polls in the Buckeye State show Kasich leading.
Both Florida and Ohio are winner-take-all delegate states, raising the stakes for all the candidates as Trump continues his march toward the Republican nomination.
With more than one-third of the delegates needed for the nomination already locked up for Trump, victories in Florida and Ohio could put the race effectively out of reach for everyone behind him.