As the Republican debate stage continues to shrink, front-runner Donald Trump came under assault from Marco Rubio, Ted Cruz and above all the moderators as never before.

The question is whether it will make any difference. As of Super Tuesday, Trump had won in two-thirds of the states that have voted in 2016. The billionaire has been under fire from his GOP primary opponents since the last debate and was denounced Thursday by 2012 Republican presidential nominee Mitt Romney.

The eleventh Republican presidential debate, held in Detroit, Mich., also featured a reunion between Trump and Fox News co-moderator Megyn Kelly, who wasted no time presenting a list of his flip-flop and position changes. The bill of particulars included Iraq and Syrian refugees.

Fellow co-moderator Chris Wallace confronted Trump on the deficits created by his tax plan, challenging the billionaire to specifically identify what offsetting cuts he would make to the federal budget beyond vague promises to root out waste, fraud and abuse. When Trump said he would cut agencies unpopular with Republicans, such as the Department of Education and the Environmental Protection Agency, Wallace retorted that his numbers didn't add up.

Trump then said he could get Medicare to save money on things like prescription drugs. Wallace responded with figures challenging the Republican front-runner's assertion that federal negotiation of drug prices would save enough money.

When Trump said that the controversy over Trump University was overblown and that the institution's Better Business Bureau grade had been changed to an "A," Kelly shot back that it was in fact a "D-."

Meanwhile, Rubio and Cruz often tag-teamed Trump. "Donald, please, I know it's hard to interrupt. Breathe, breathe, breathe," Cruz told Trump during a heated exchange over Supreme Court Chief Justice John Roberts. "You can do it. You can breathe. I know it's hard. I know it's hard…"

"When they're done with the yoga, can I answer a question?" Rubio asked.

"I really hope that we don't see yoga on this stage," Cruz replied, prompting Rubio to say of Trump, "Well, he's very flexible so you'd never know."

Trump explicitly backtracked on high-skilled immigration. "I'm changing it and I'm softening the position because we have to have talented people in this country," he admitted during the debate. Trump was also challenged to agree to release tapes in which he allegedly told the New York Times editorial board his position on immigration was flexible.

While immigration has been Trump's signature issue and he received the endorsement of leading immigration hawk Sen. Jeff Sessions, R-Ala., before Super Tuesday, it was just the latest sign he has little familiarity with the formal policy plan outlined on his campaign website.

Yet Trump mostly maintained his composure compared to the previous debate and the one before the South Carolina primary, despite occasionally yelling over his opponents' responses and repeatedly calling Rubio "Little Marco," the absentee senator with the "worst voting record."

Trump also responded to jibes by Rubio and others about his small fingers by appearing to suggest he had a large penis.

In the end, despite escalating criticism of Trump, a coming barrage of anti-Trump ads in Florida and other key primary states and a Twitter hashtag promoted by conservatives who say they will refuse to support the reality television star if he is the nominee, the other three Republican presidential candidates all pledged to back Trump if he wins.

Rubio focused his attacks on Trump's honesty and trustworthiness, as well as his business record. Cruz preferred to assail Trump's conservative credentials, though he also said, "Donald has a tenuous relationship with the truth."

John Kasich, the governor of Ohio and the lowest-polling candidate left in the race, mostly tried to stay above the fray. Kasich boasted of his role in delivering the last balanced federal budget "not because I worship at the shrine of the balanced budget" and appeared to backtrack on religious liberty.

"Don't sue, hire another photographer," Kasich said of lawsuits against wedding vendors that do not wish to work same-sex weddings. He had previously said serving all customers was the price of engaging in commerce.