As results showed Donald Trump leading in at least six states on Super Tuesday, Sens. Ted Cruz (R-Tex.) and Marco Rubio (R-Fla.) argued that nominating him would be bad for the Republican party. Here are key moments from their speeches following the March 1 races. (Sarah Parnass/The Washington Post)

Donald Trump won GOP primaries in seven states and Sen. Ted Cruz took three in a Super Tuesday rebound, sparking renewed calls from some Republicans to unify around a single Trump rival as the billionaire tightened his hold on front-runner status.

The contests in 11 states showcased Trump’s dominance over a crowded GOP field. Sen. Marco Rubio (Fla.) was the winner in one state: Minnesota, his first victory of the 2016 primary season.

Trump won Alabama, Arkansas, Georgia, Massachusetts, Tennessee, Vermont and Virginia, according to Edison Media Research. In several states, his lead was in double digits, and his share of the GOP vote neared 50 percent. With those wins, Trump has more than doubled his victory total in this GOP primary season.

But even as Trump basked in his Super Tuesday romp, a well-funded super PAC was ramping up its effort to discredit the New York businessman with a new television advertisement that portrays him as a predatory huckster who scammed working- and middle-class Americans.

The 60-second ad, which will begin airing Wednesday on stations across the country at a cost of more than $1 million, centers on Trump University, the billionaire mogul’s for-profit enterprise that promised to teach students the tricks of the real estate trade and is now defunct and the subject of a fraud suit.

The attack echoes themes that Rubio, who is trying to unite the GOP’s anti-Trump forces under his own banner, has advanced as he has addressed swelling crowds in suburban areas.

Cruz won Alaska, Oklahoma and his home state of Texas just after 9 p.m. These are the second, third and fourth states Cruz has won in this race; he also won the Iowa caucuses, the first contest of all. The win in Texas, in particular, was vital: It saved Cruz from a humiliating home-state defeat and gave him part of the largest slate of delegates that was up for grabs Tuesday.

But this was not the Super Tuesday that Cruz had hoped for months ago. He had campaigned hard in Southern states, hoping to dominate among evangelicals and very conservative voters. Instead, in state after state, he saw those voters flock to Trump.

For Rubio, the Minnesota win was a boost he sorely needed. Earlier in the night, Trump had mocked him for not winning any states so far. But overall, Tuesday was a disappointment for Rubio. He had attacked Trump sharply in the past few days and shifted some late-deciding voters into his camp. But outside of Minnesota, it wasn’t enough.

Ohio Gov. John Kasich came in a close second to Trump in Vermont.

Virginia primary exit poll results

The worry among the party establishment — which has put its last hopes on Rubio — was strong and growing after Trump’s Tuesday victories.

Even Sen. Lindsey O. Graham (R-S.C.), an outspoken critic of Cruz, said to CBS’s Charlie Rose on Tuesday night, “Well, I think we’re about ready to lose to the most dishonest politician in America, Hillary Clinton, and how could you do that?”

“I made a joke about Ted, but we may be in a position to have to rally around Ted Cruz as the only way to stop Donald Trump, and I’m not so sure that would work,” he said, adding that when it came to that prospect,“I can’t believe I would say yes, but yes.”

Cruz addressed his supporters at a venue called the Redneck Country Club in Stafford, Tex. He sought not so subtly to convince Rubio to drop out of the race, saying that a divided field was allowing Trump to succeed.

“So long as the field remains divided, Donald Trump’s path to the nomination remains more likely. And that would be a disaster . . . for conservatives, and for the nation. And after tonight, we have seen that our campaign is the only campaign that has beaten, that can beat, and that will beat Donald Trump,” Cruz said. He spoke to primary voters in future states: “We must come together.”

Rubio, the establishment candidate who had sharply attacked Trump in the past few days, ran close to Trump in Virginia, boosted by support among college-educated voters and Republicans in the Washington, D.C., suburbs. But he fell short, with Trump piling up large margins in the state’s rural South and West.

Still, exit polls showed some good news for Rubio: In several states, he did well among voters who decided late, according to media reports. That could be taken as proof that Rubio’s late attacks on Trump worked — and it could encourage Rubio to continue them, hoping to win more primaries in the coming weeks.

“Just five days ago, we began to unmask the true nature of the front-runner so far in this race. Five days ago, we began to explain to the American people that Donald Trump is a con artist. And in just five days, we have seen the impact it is having all across the country,” Rubio told supporters in Miami. “We are seeing, in state after state, his numbers coming down. Our numbers going up.”

He looked ahead to the Republican primary in Florida on March 15, a “winner-take-all” contest that could vault Rubio back into contention — or, if he loses, doom him.

Rubio’s campaign has sought to position him as the top alternative to Trump: the one who’d be waiting and ready when voters — or delegates, at a fractious GOP convention — finally turned on the front-runner. But Tuesday’s results showed that isn’t exactly true. In six of the nine states where polls have closed, in fact, Rubio was running third.

Trump spoke to supporters at his Mar-a-Lago resort in Palm Beach, Fla., in an ornate ballroom. In his speech, he mocked Rubio, calling him “the little senator” and reminding his crowd that “[Rubio] didn’t win anything. He hasn’t won anything, period.”

Trump also called his campaign “a movement,” and sought to look ahead to a general election contest against Clinton, the former secretary of state.

“I am a unifier. When we get all of this finished, I’m going to go after one person, Hillary Clinton,” Trump said. He rejected suggestions that his comments — about Mexican immigrants, mass deportation of undocumented immigrants and a ban on Muslim foreigners entering the country — had divided his party.

“We are going to be a much finer party. We’re going to be a unified party,” Trump said. “I mean, to be honest with you. And we are going to be a much bigger party. Our party is expanding.”

Later, Trump responded to a question by saying he’d been watching all the big cable-TV news networks, and liked them all. “See, I’m becoming diplomatic,” he said.

In a wide-ranging news conference that followed Trump’s speech, he issued a kind of threat to House Speaker Paul Ryan (R-Wis.), who – before Trump came on the scene – had a claim to being the most popular figure in the GOP.

“Paul Ryan, I don’t know him well,” Trump said. “I’m sure I’ll get along with him. And if I don’t? He’ll have to pay a big price.”

It seemed possible, given Tuesday’s results, that Rubio, Cruz and Kasich could find a reason to remain in the race. So even where Trump lost Tuesday night, he may have won — reaping the benefits of a crowded field of candidates and splitting the anti-Trump vote into pieces.

Former pediatric neurosurgeon Ben Carson, who has failed to win a single primary or caucus so far, told supporters he was dismayed with the state of the nation’s political system and not prepared to quit the race yet.

“It is rotten; it is rotten to the core,” Carson told a crowd of supporters in Baltimore. “I’m not ready to quit untangling it quite yet.”

Carson has called on the five remaining candidates to meet privately in Detroit in advance of Thursday’s upcoming GOP Fox News Channel debate. He has asked them to take “a pledge to talk about the many serious problems facing our country, instead of personally attacking each other.”

In the Democratic race, with nearly all the votes counted,Clinton won the Alabama, Arkansas, Georgia, Tennessee, Texas and Virginia Democratic primaries as she looks to dramatically widen her lead in the race for the Democratic presidential nomination over Vermont Sen. Bernie Sanders.

Sanders chalked up four victories: his home state of Vermont, as well as in Oklahoma, Minnesota and Colorado.

At a polling place in Houston where Cruz cast his vote Tuesday, Francisco Valle, 74, held a sign depicting Trump with a Hitler-style mustache and his right hand raised; it read, “absolutely no Mexicans.” Valle also hung a sign with the letter T and word “Trump” in the shape of a swastika with “STOP” written beneath.

“I am here because I want to make awareness of a movement that is very dangerous to all the minorities, because Hitler started the same way,” said Valle, who is Mexican American. “He blamed the Jews for all the problems, and now Trump is blaming the Mexicans for the problems.”

Trump has suggested he is expanding the GOP’s base of support by appealing to Democrats and independents, even though some say he is alienating some traditional Republican backers.

“We have tremendous numbers of people coming in, and the Republican Party is growing larger,” he said. If it fails to do that, he added, “it’s not going to win.”

Wagner reported from Burlington, Vt.; Eilperin from Washington. Katie Zezima in Houston; Patricia Sullivan in Arlington, Va.; Laura Vozzella in Richmond, Va.; Abby Phillip in Minneapolis, Minn.; Scott Clement, Anne Gearan and Paul Kane in Washington; Robert Costa in Atlanta; Jose A. DelReal in Nashville; Fenit Nirappil in Norfolk, Va.; Ed O’Keefe in Alcoa, Tenn.; and David Weigel in Castleton, Vt., contributed to this report.