Donald J. Trump won sweeping victories across the South and in New England on Tuesday, a show of strength in the Republican primary campaign that underscored the breadth of his appeal and helped him begin to amass a wide delegate advantage despite growing resistance to his candidacy among party leaders.
Trump’s political coalition — with his lopsided victories in Alabama, Georgia, Massachusetts and Tennessee, and narrower ones in Arkansas, Vermont and Virginia — appears to have transcended the regional and ideological divisions that have shaped the Republican Party in recent years.
With strong support from low-income white voters, especially those without college degrees, he dominated in moderate, secular-leaning Massachusetts just as easily as he did in the conservative and heavily evangelical Deep South.
Brandishing his Super Tuesday victories as proof of his political might, Trump said he expected to consolidate the Republican Party behind his campaign.
“I am a unifier,’’ he told reporters at his Mar-a-Lago resort in Palm Beach, Florida, after the winners of about half the day’s contests had been declared. “Once we get all of this finished, I am going to go after one person: Hillary Clinton.’’
Sen. Ted Cruz reasserted himself with victories in his home state, Texas, neighboring Oklahoma and Alaska, earning a reprieve as he fends off questions about his viability. The wins strengthened his case that he is the only alternative capable of overtaking Trump.
The results were a grievous setback for Sen. Marco Rubio of Florida, who has insistently argued that among the Republican candidates, only he has the political standing to compete with Trump in a head-to-head race. Rubio’s backers have urged other candidates to stand down and allow him a clean shot at Trump, who is a polarizing figure even among Republican primary voters.
Cruz outpolled Rubio in many of the states that voted Tuesday, however, especially in the South, and was the only candidate other than Trump to win more than one state. Though Rubio handily won the Minnesota caucuses, his otherwise limp finish may have cost him any leverage he had to demand that other candidates defer to him.
Still, Rubio urged Republicans not to give up hope of thwarting Trump.
“Do not give in to the fear, do not give in to anger, do not give in to sham artists and con artists who try to take advantage of your suffering,’’ he said in Miami. “I will campaign as long as it takes and wherever it takes to ensure that I am the next president of the United States.’’
In the states Trump carried, there was a smattering of resistance in a band of relatively affluent suburbs, including areas outside Atlanta and Washington that supported Rubio, and areas around Boston that voted for Gov. John Kasich of Ohio.
Republican strategists have expressed fear that in the general election, Trump would struggle to win the support of suburban women and white-collar voters who might otherwise lean Republican but might recoil from his caustic and racially charged approach to politics.
Several of the states that Trump won, including Massachusetts and Tennessee, had appeared at one point to be favorable to a mainstream opponent, and Rubio and Kasich both visited those states often.
But no candidate invested more in success on Super Tuesday than Cruz, who spent many days last year campaigning across the South, far afield of the first nominating states, Iowa and New Hampshire.
Cruz has argued consistently that only a candidate with an unblemished conservative record could mount a strong challenge to Trump over the long run. The outcome in Texas, the most populous state to vote Tuesday, will also increase his delegate count as candidates jockey for position in a potentially contested Republican National Convention.
Still, Cruz also showed the limits of his political reach: He did not come close to Trump in much of the South, he failed to resonate in more moderate Massachusetts and Virginia, and the lineup of states that vote later in March may be less hospitable to his brand of rigidly ideological politics.
Cruz, appearing in Stafford, Texas, boasted of his victories but acknowledged that the splintered opposition would make Trump difficult to stop.
“So long as the field remains divided, Donald Trump’s path to the nomination remains more likely, and that would be a disaster for Republicans, for conservatives and for the nation,’’ he said, referring to Trump as “profane and vulgar.’’
Cruz did not directly mention Rubio, but pleaded with those rivals who had not had similar successes in the primaries to “prayerfully consider coming together’’ to halt Trump.
Both Cruz and Rubio have adopted a survival strategy geared less toward defeating Trump outright than toward denying him the delegates he needs to clinch the nomination before the summer convention.
But the stakes for the party’s anti-Trump forces have risen in recent days: With Trump’s initial refusal on Sunday to disavow the support of the Ku Klux Klan and its former grand wizard David Duke, only his latest inflammatory episode, he reinforced the fears of Republican leaders that nominating him would be a historic mistake for the party.
Republicans have been increasingly outspoken in recent days, warning that if Trump is the nominee, it will consign the party to a general election catastrophe.
Party leaders embarked on a last-ditch effort in recent weeks to throw up a united front of resistance to Trump, perhaps by clearing the field of opponents so that a single challenger can compete with him, or by directing a late wave of negative advertising against Trump in the biggest states that award their delegates in March.
On Tuesday, several financial patrons of the Republican Party organized a phone call to drum up funding for an anti-Trump effort. Helping lead the call were hedge-fund manager Paul E. Singer; Chicago Cubs co-owner Todd Ricketts; and Meg Whitman, the Hewlett-Packard executive and former candidate for governor of California. It is unclear what kind of political offensive may emerge from those discussions.
A handful of outside groups have announced plans to attack Trump in television commercials in the coming weeks, including a super PAC backed by Ricketts and a conservative nonprofit group, the American Future Fund, that has unveiled ads blasting Trump for backing a failed education company that is being sued for fraud.
Without some sort of extraordinary external intervention or an act of political sacrifice from one or more of his opponents, the only real prospect of stopping Trump’s nomination may come through the political equivalent of a gang tackle, with a cluster of candidates effectively banding together to accrue delegates and deny Trump a majority.
Advisers to Rubio and Kasich have acknowledged that a contested convention may be their most realistic chance at claiming the Republican nomination, and that they may have a better chance of blocking Trump from winning the 1,237 delegates he needs to be nominated than of taking a majority themselves.
Trump added at least 190 delegates, for a total of more than 270, extending his advantage to more than triple the delegates of Cruz, his nearest rival. But because Tuesday’s contests allocated delegates proportionally, his victories fell short of offering him an impregnable lead. Rubio, however, was in danger of failing to reach the vote threshold, 20 percent, to receive any at-large delegates in Alabama, Texas and Vermont.
In a sign of his determination to lock up the nomination swiftly, Trump visited two symbolically important states on Super Tuesday: Ohio, where Kasich is governor, and Florida, Rubio’s home state.
Both states are set to award their delegates on March 15, and Trump hopes that by winning both, he can drive his opponents out of the race.
Trump trained his fire on Rubio in his Palm Beach news conference Tuesday night, belittling him as “a lightweight’’ and a “little senator.’’
He dismissed threats from a handful of Republicans who have said they may back a third-party candidate over him. On the contrary, he insisted he would expand the Republican coalition. “We are going to be a much bigger party, and you can see that happening,’’ he said.
Two other candidates, Kasich and Ben Carson, a retired neurosurgeon, appeared unlikely to gain any momentum on Tuesday.
While Kasich ran close to Trump in Vermont, he will have to enter a third contest he has targeted, Michigan’s primary on March 8, with no particular improvement in his fortunes.
Kasich sought to put the best face on the wide losses he suffered Tuesday, crowing to a small crowd in Jackson, Mississippi, “Tonight, I can say that we have absolutely exceeded expectations.’’
Straining to find a bright spot on the map, he noted, “We are running, right now, neck and neck with Donald Trump in the state of Vermont.’’
Carson has ceased to be much of a factor in the race. He has languished at the bottom of polls and has not broken through in any recent debates.
He spent Tuesday night in a state that did not vote, holding his party in Baltimore, where he was a longtime neurosurgeon at Johns Hopkins University.