Four debates in, the previously fluid dynamics in the Republican presidential race appear to have solidified. Despite furious efforts on the part of every other candidate, the top three contenders for the nomination clung to their advantages.

The top eight candidates squared off in a primetime debate hosted by the Fox Business network and held in Milwaukee. An undercard debate earlier in the evening featured four of the runners-up.

After a furor over moderators' aggressive tone in the last debate, Tuesday's hosts from Fox Business News allowed the eight candidates to deliver lengthy, uninterrupted answers and avoided attempts to get them to engage with one another.

Notable on the day that the Fight for $15 effort to raise the minimum wage launched coordinated protests nationwide, many of the candidates spoke out against such a policy move. Democratic front-runner Hillary Clinton has called for raising the minimum wage from $7.25 an hour to $12. Her chief rival, Vermont Sen. Bernie Sanders, has backed an increase to $15.

Though Donald Trump was able to monopolize some of the earlier debates, he was less of a central presence in Tuesday’s primetime engagement. But he still held his own at several key moments, including during some testy exchanges with Ohio Gov. John Kasich and Sen. Rand Paul of Kentucky.

Ben Carson, second in national polls, got an opportunity to push back on some of the recent questions regarding his biography. And Florida Sen. Marco Rubio, polished as ever, seemed likely to keep a grip on his new position as the GOP establishment’s favorite, despite the best efforts of onetime heir apparent Jeb Bush.

Advisers for Bush — the frontrunner in the 2016 Republican contest until Trump surged in the polls this summer — had suggested their candidate would begin his comeback on Tuesday night with an energetic, feisty performance. And he did at times adopt a more aggressive posture than he had in prior debates, such as when he pushed back on Trump’s proposal to deport millions of undocumented immigrants.

“They’re doing high fives right now in the Clinton campaign right now,” said Bush, implying that Trump’s hardline stance would hurt the Republican party’s shot at capturing some of the Latino vote.

The other candidates outside of the top three — including Kasich, Paul, former Hewlett-Packard CEO Carly Fiorina, and Texas Sen. Ted Cruz — also had their moments as they tried to break apart the campaign status quo.

Kasich interjected frequently and appeared intent on distinguishing himself as one of the more forthright, no-nonsense candidates. He derided Trump’s deportation plan as “silly” and defended the 2008 financial sector bailout against several other candidates by insisting the government could not “turn a blind eye” to the threat that households would see their savings disappear.

Fiorina spoke repeatedly of the need to “take our country back,” while Paul sparred with Trump and Rubio on separate occasions, accusing the latter in particular of failing to propose a conservative tax reform plan.

“How is it conservative to add a trillion-dollar expenditure to the federal government?” asked Paul, referring to Rubio’s call for a child tax credit.

Paul and Rubio also fought over military spending, with Paul insisting that a large defense budget is not consistent with conservative principles.

“We cannot even have an economy if we’re not safe,” said Rubio, alluding both to his support for a robust defense budget and the Tuesday debate’s nominal status as an economy-focused affair.

“If you think defending this nation is expensive, try not defending it,” seconded Cruz.

Rubio's call for more military spending was backed by Trump, who also he delved into the policy discussions in Tuesday's debate, including outlining his opposition to a new Asia-Pacific trade deal supported by many Republicans.

The Trans-Pacific Partnership (TPP) trade pact signed last month by President Barack Obama with 11 other nations “was designed for China to come in through the back door and take advantage of everyone. … China takes advantage (of the U.S.) through currency manipulation.”

Paul corrected Trump, saying, “We might want to point out China is not part of this deal.”

Other candidates launched themselves at Trump after the frontrunner said he wouldn’t mind if Russian President Vladimir Putin decided to “knock the hell out of” the Islamic State in Iraq and the Levant (ISIL). Russia has inserted itself into the ongoing Syrian conflict, in alliance with Syrian President Bashar Al-Assad, against rebel forces that include ISIL.

Bush replied that Trump’s proposed strategy of letting Assad, Putin, and ISIL snipe at each other was “like a board game.”

“That’s not how the world works,” he said.

The inaccuracies in Carson’s autobiography, a subject of much press attention in the week running up to the debate, received scarcely a mention from anyone onstage. Carson — who had admitted a few days prior that he had never been admitted into the West Point military academy, in seeming contradiction to a story in his autobiography — answered a question from a moderator about it early on, but none of the other candidates made much of it.

“I have no problem with being vetted, but I do have a problem with being lied about,” said Carson, who suggested he was being subjected to a media double standard compared to Hillary Clinton.

Carson was cheered by the debate audience when he suggested he was facing tougher scrutiny than Clinton. But he appeared to flounder on some policy questions, including a disconnected answer about whether he would break up big banks.

Cruz repeatedly played the populist. He railed against the “Washington cartel,” big government and even big banks. But in moment reminiscent of former Texas Gov. Rick Perry's “oops” debate debacle, Cruz blanked when it came to naming the five departments he would eliminate.

“The IRS, the Department of Commerce, the Department of Energy, ah, the Department of Commerce and HUD,” Cruz said.

Fox Business News moderator Maria Bartiromo ignited a chorus of boos from the audience by referring to Clinton's resume as “impressive.” But the veteran anchor plowed ahead with her question to Rubio about how his experience makes him worthy of the presidency.

Rubio responded that “this election is about the future, about what kind of nation we're going to be in the 21st century.”

Cruz couldn't let an opportunity to strike at Clinton go unanswered, saying “Hillary Clinton embodies the cronyism of Washington.”

Closing statements focused on fiscal policy, the future and Clinton.

Trump said “we cannot let Hillary Clinton, who is the worst secretary of state in the history of our country, win this election.” Fiorina said a “Clinton presidency will corrode the character of this nation.” And Kasich said he worried about what would happen if Clinton or Bernie Sanders won the presidency.

Paul argued he was the “only fiscal conservative on stage.” Cruz stressed his commitment to “free-market principles.”

Rubio repeated his forward-looking message, promising a “new American century.” Bush pledged to be a commander-in-chief, not a “divider-in-chief.”

Carson spoke of several issues, including drug overdoses, rising debt and abortion. He said it was time to change the “narrative,” adding, “there is something special about this nation and we must embrace it and be proud of it and never give it away for the sake of political correctness.”

The field returns to the campaign trail on Wednesday where polls will determine if any of the candidates other than Trump, Carson and Rubio were successful in disrupting the campaign hierarchy. The next Republican debate, hosted by CNN, will take place Dec. 15, in Las Vegas.

With The Associated Press