Bodyguards escorted Univison's Jorge Ramos out of Republican presidential candidate Donald Trump's news conference Aug. 25. After guards let the reporter back in, he went back and forth with Trump about his immigration plan. (MSNBC/Asya Akça, Radio Iowa)

To anyone who thought Donald Trump might soften his tone after a new round of criticism of his presidential campaign, the Republican front-runner proved here Tuesday night that he will not be tamed.

Trump booted the nation’s top Latino newsman out of his press conference, but moments later he let Univision’s Jorge Ramos reclaim his seat in the front row and the two men sparred passionately about illegal immigration.

Next, Trump added to his enemies list. He refused to apologize to Fox News anchor Megyn Kelly, whom he ridiculed anew on Twitter Monday night. He launched fresh attacks against Wisconsin Gov. Scott Walker and Sen. Marco Rubio of Florida. And he sprinkled spicy slams on former Florida governor Jeb Bush throughout his speech at a rollicking rally.

To top it off, Trump went after the entire political class in Trumpian fashion, saying he wants to outlaw Teleprompters (one of his best applause lines of the night) and asserting that as soon as politicians get to Washington, they become “impotent.”

“They look at these beautiful buildings, these beautiful halls and all of a sudden they become impotent,” Trump said, as the crowd laughed. “Is that an appropriate word? I think so.”

Trump’s lively visit to Dubuque, where he rallied an estimated 3,500 supporters inside a convention hall on the banks of the Mississippi River, comes as he expands his campaign in Iowa and other key states.

Trump appeared on stage with Sam Clovis, a prominent Iowa conservative activist who had been former Texas governor Rick Perry’s state chairman but abruptly defected from Perry’s camp because of fundraising troubles. Trump poached Clovis and named him a national co-chairman and policy adviser. Trump’s top Iowa strategist, veteran organizer Chuck Laudner, is a friend of Clovis and had been courting Clovis for weeks.

Trump also announced five additional staffers in several early-voting states, including Charles Munoz as his Nevada state director. In South Carolina, Nancy Mace, the first female graduate of the Citadel, is now Trump’s state coalitions director, while James Epley is his upstate regional director. He announced hires in New Hampshire as well.

Trump, who is leading GOP polls nationally, said in an interview that he is determined to expand his campaign in the coming weeks, moving from a small circle of aides to a national grass-roots operation that he hopes will sustain the momentum he has built this summer with raucous speeches and seemingly nonstop appearances on television talk shows.

“They said I wouldn’t run. They said I would not file the papers. They said I didn’t have a campaign,” Trump said, with a hint of exasperation. “Well, I did — and I do.”

Two minutes into Trump’s news conference here on Tuesday, the candidate had a tense exchange with Ramos, one of the country’s most recognizable Mexican-Americans.

Ramos stood up in the front row of journalists to ask Trump about his plan to combat illegal immigration. But Trump did not want to answer.

“Excuse me,” Trump said. “Sit down. You weren’t called. Sit down.”

Ramos, holding a piece of paper, calmly said, “I’m a reporter, an immigrant, a senior citizen. I have the right to ask a question.”

Trump interrupted him. “Go back to Univision,” he said. Then Trump motioned to one of his bodyguards, who walked across the room and physically removed Ramos from the room.

The ejection lit up social media. Reporters asked Trump why he removed Ramos. At first, he accused Ramos of violating his news conference protocol. “He stood up and started screaming,” Trump said of Ramos. “He’s obviously a very emotional person.”

But moments later, Ramos returned to his seat in the front row — and Trump called on him. For five minutes, they tangled over immigration policy, an issue on which both men have passionately different views.

“Here’s the problem with your immigration plan,” Ramos said. “It’s full of empty promises.”

Ramos pointed out it would be unconstitutional to deny citizenship to what Trump calls “anchor babies,” children born in the United States to undocumented immigrants. Trump disagreed, saying it could be done as an act of Congress and that some legal scholars argue the 14th Amendment should be changed.

“A woman’s getting ready to have a baby,” Trump said. “She crosses the border for one day, has the baby, all of a sudden for the next 80 years — we have to take care of” the child.

The next question from Ramos: How do you build a 1,900-mile wall across the U.S. border with Mexico?

“It’s very easy,” Trump said. “I’m a builder. . .What’s more complicated is building a building that’s 95 stories tall.”

The questioning continued. At one point, Trump said, “I can’t deal with this.” A Trump aide interrupted and told Ramos, “Is there one question — one question?”

Yet Trump let the questioning continue, seemingly determined to prove his case. “I have a bigger heart than you do,” he told Ramos. “We’re going to do [deportations] in a very humane fashion.”

Trump went on to assert that gang members in Baltimore, St. Louis and other cities are illegal immigrants.

“Listen, we have tremendous crime,” he told Ramos. “We have some very bad ones. Do you mind if I send them back to Mexico?”

Ramos replied, “No human being is illegal, Mr. Trump.”

The candidate’s response: “Well, when they cross the border, from a legal standpoint, they’re illegal immigrants when they don’t have their papers.”

When Ramos pressed Trump on polls showing his unpopularity with Latinos, Trump would not accept the premise and turned the question on him: “How much am I suing Univision for right now? Do you know the number? I know you’re part of the lawsuit.”

“I’m a reporter,” Ramos said.

“Five hundred million dollars,” Trump replied. “And they’re very concerned about it, by the way. I’m very good at this.”

Costa reported from Washington.