Nikki Haley is said to be planning to drop out of the presidential race. Follow for live updates.

Donald J. Trump rolled up victories across the country on Super Tuesday, and by the end of the evening it was clear that the former president had left Nikki Haley in the delegate dust.

Mr. Trump’s coast-to-coast wins — in California, North Carolina, Tennessee, Texas, Virginia and beyond — brought a new mathematical certainty to what has been the political reality for some time: He is all but certain to capture the Republican Party’s presidential nomination.

Ms. Haley plans to make it official on Wednesday morning, according to multiple people familiar with her plans, with an event where she will drop out but not immediately offer her endorsement to Mr. Trump. Instead, she will say he must work to win over her voters.

That is important because tucked inside Mr. Trump’s often dominant statewide victories on Tuesday were signs of vulnerability for the fall. He showed some of the same weakness in the swingy suburban areas that cost him the White House in 2020.

The presidential primaries on Super Tuesday, along with a series of congressional contests in key districts, many still undecided, offered the broadest look yet at the preferences of voters in both parties headed into the 2024 election. Here are five takeaways from the results:

An unstoppable Mr. Trump continues to roll.

Roughly one-third of the nation voted on Tuesday but there was little drama. News outlets called state after state soon after polls closed, just as they have since Mr. Trump topped 50 percent in Iowa’s kickoff caucuses.

The exception was Vermont, where Ms. Haley scored her first state victory (she won Washington, D.C., over the weekend). But that was a small island in a sea of Trump landslides in more than a dozen other states, including Alabama, where he was above 80 percent.

There was so little for Ms. Haley to spin on Tuesday that she skipped any public remarks at all, watching returns behind closed doors in Charleston, S.C. An aide said music was blaring and the mood upbeat, suggesting that her campaign had become about delivering a message as much as accumulating delegates.

In a sign that Mr. Trump was already more focused on the fall, he has recently picked primary states that also happen to be November battlegrounds for his campaign events. He went to North Carolina last weekend, for instance, ahead of Super Tuesday and is headed to Georgia this coming weekend before its March 12 primary.

On Tuesday, Mr. Trump held a party at Mar-a-Lago, his private club in Florida. (He has spent around $315,000 in campaign funds at Mar-a-Lago since announcing his 2024 run, records show.)

“It’s been a big night,” he declared.

The bigger night for Mr. Trump — actually securing the delegates needed to ensure his nomination — could come as early as March 12 or March 19.

There are warning signs for Trump in the Haley vote.

At this point, the Biden team is studying Ms. Haley’s showing in suburban areas almost as closely as the Trump operation is, if not more.

The most important fall battleground that voted on Tuesday was North Carolina, a state Mr. Trump only narrowly won in 2020. And while Mr. Trump won the primary there with roughly 75 percent of the vote, he was weakest in the counties encompassing and surrounding Raleigh and Charlotte, ahead in Mecklenburg County by only seven percentage points.

Exit polling told another part of the story.

A majority of Ms. Haley’s primary voters said they were voting against her opponent more than for her, a sign of anti-Trump motivation that could last until November. And even in defeat, she was leading among moderate voters by nearly two to one. Her problem was that moderates make up only 20 percent of the voters in a G.O.P. primary. But in a close general election, those voters may matter more.

Overall, roughly one in four Republican primary voters in North Carolina said they would feel dissatisfied if Mr. Trump won the nomination.

“In state after state, there remains a large bloc of Republican primary voters who are expressing deep concerns about Donald Trump,” Olivia Perez-Cubas, a spokeswoman for the Haley campaign, said late Tuesday.

In dropping out, Ms. Haley is not expected to immediately back Mr. Trump the way another primary rival, Gov. Ron DeSantis of Florida, did. She will challenge Mr. Trump to earn the support of her voters, which she called “not some tiny group” after South Carolina’s primary.

The educational divide inside the Republican Party was especially stark on Tuesday. Mr. Trump was only narrowly carrying Republican primary voters with college degrees in North Carolina, 51 percent to 45 percent, but he was crushing Ms. Haley, 80 percent to 15 percent, among Republican voters without a college degree.

In other words, Mr. Trump’s base is delivering him the nomination. But he may need to bring other voters into his coalition to win in the fall.

Democrats bruised Biden — again.

Mr. Biden, who has had only nominal opposition for the Democratic nomination, also rolled to big-margin victories across the country: Alabama, Maine, Massachusetts, Tennessee, Texas, Vermont and Virginia, to name a few. By the end of the night, he swept all 15 states.

But yet again there were flashing lights for a president who is struggling to rally the whole of his party behind him. Nearly 20 percent of Democrats in Minnesota voted uncommitted, in an apparent protest vote against Mr. Biden’s support of the Israel military response to the Hamas terrorist attack of Oct 7. Mr. Biden won less than two-thirds of the vote in Hennepin County, home to Minneapolis.

The protest was an extension of a campaign that started in Michigan last week, when 13 percent of Democrats voted uncommitted. The larger share in a state with fewer Arab American voters — but a large and active progressive wing — suggested that the movement of voters pressing Mr. Biden for a policy change was gaining traction.

There were other signs, too. In Colorado, the noncommitted vote was 8 percent. The “no preference” vote in North Carolina hit nearly 13 percent; it’s worth noting as Mr. Biden considers contesting a state that Mr. Trump won by a whisker in 2020.

It is far from clear what those voters will do this November. But should they back Mr. Trump, support a third-party candidate or just stay home, they could cost Mr. Biden a close election.

Minnesota wasn’t the only state that cast a bit of a cloud over Mr. Biden’s night. In a small indignity for the sitting president, Mr. Biden tied in the delegate race in American Samoa to Jason Palmer, an entrepreneur. (It’s really OK if you have never heard of him before tonight.) There are no Electoral College votes in American Samoa.

A Trump speech previews dark themes for the fall.

When Mr. Trump won in Iowa in January, he pulled aides onstage for an impromptu celebration. He did the same in the next contest, inviting supporters alongside him in New Hampshire. And then again in South Carolina.

But on Super Tuesday, Mr. Trump stepped onto the stage solo. Then he never mentioned Ms. Haley’s name.

The imagery and messaging were unmistakable: Mr. Trump is focused on Mr. Biden and prosecuting a case that America has darkened since he departed, with a particular focus on immigration, inflation and international affairs.

“Frankly our country is dying,” Mr. Trump said.

He was speaking in typical hyperbole but tapping into a real sentiment. The recent New York Times/Siena College poll showed 65 percent of registered voters believe the nation is headed in the wrong direction — including 42 percent of Democrats.

A week after Mr. Trump and Mr. Biden both traveled to the border, the former president returned over and over to the issue that now animates much of his stump speech.

He also tried to make his case on his handling of Covid (“We never got credit for that”), the stock market (“That’s doing well because our poll numbers are so much higher than Joe Biden’s”) and how the nation’s worldwide standing had plummeted since he departed (“The world is laughing at us”).

California’s top-two primary system was an early loser.

There were two winners in the California Senate primary on Tuesday night: Representative Adam Schiff, a Democrat, and Steve Garvey, the former Los Angeles Dodger and a Republican.

But there also was, arguably, one clear loser: the top-two, nonpartisan primary system that California voters adopted in 2010. The system was sold as good government reform, meant to drain partisanship and promote centrist politicians. Instead, it showed itself — again — to be as vulnerable as traditional primaries to partisan political gamesmanship.

Mr. Schiff, one of two leading Democrats in the contest to fill the seat held by Senator Dianne Feinstein, and allies spent millions of dollars boosting Mr. Garvey.

Mr. Garvey, who barely campaigned, has little chance of being the next senator from overwhelmingly Democratic California. But Mr. Schiff wanted to run against a Republican in the runoff rather than Representative Katie Porter, a Democrat with sizable support among progressives.

Supporters of Ms. Porter also tried to game the system, albeit not as aggressively as Mr. Schiff, by bolstering the prospects of another Republican on the ballot, Eric Early, to pull Republican support from Mr. Garvey.

One unintended result: Republican voters, who have been increasingly marginalized in statewide races as California has grown more and more Democratic, ended up having at least a little bit of a say in picking the state’s next senator.