The voters in a dozen states on Tuesday cemented the leads of businessman Donald J. Trump and former Secretary of State Hillary Clinton, who claimed compelling victories and ended the evening with sizable leads in the delegate count for their parties’ respective nominating contests.

But even as Mr. Trump, whose seven victories stretched from the liberal Northeast to the evangelical-rich Deep South, solidified his standing as the Republican frontrunner, the mechanics of the primary calendar and the complex math of delegate allocation promises that the GOP contest will be stretched for a spell longer

Republican Results

The Republican Super Tuesday process marked a dizzying array of rules—a blend of both open and closed primaries and caucuses, plus varying thresholds for statewide allocation and for winner-take-most—that struck damaging blows to the campaigns of Mr. Trump’s chief rivals, Senators Ted Cruz of Texas and Marco Rubio of Florida.

While both men finished the night on the leaderboard (Cruz won three states, including his delegate-rich home state and Rubio notched his first win of the race in Minnesota) and earned second- and third-place delegates elsewhere, both Rubio and Cruz trailed in the final delegate count.

The Republican Road Ahead

To secure the Republican nomination, 1,237 delegates are necessary, and all candidates remain far from that threshold.

While the early nominating states play an outsized role in shaping the contours of the race, only a few delegates are awarded to the winner. And because delegate allocation in these early contests offer mostly proportional models in which all candidates win a share according to their vote margin, Mr. Trump has not yet taken a dramatic lead in the delegate race. For now.

To date, Trump has secured just 316 delegates. His closest rival, Sen. Cruz, trails with 226, while Sen. Rubio places third, with 106.

Another nine states, all proportional, will vote within the next week in the Republican race. But then the nature of the contest will shift on March 15 to winner-take-all and hybrid models. When the dust settles on March 16, 58 percent of all delegates will have been awarded in the Republican contest.

Historically, eventual nominees have amassed the necessary number of delegates once 50 to 70 percent of primary electors have been awarded. That means Sens. Cruz and Rubio have roughly two weeks to stage an upset.

Democratic Results

But if the window of opportunity for the also-runners in the Republican race is narrow, it’s narrower still for Vermont Senator Bernie Sanders, whose four victories Tuesday were confined to his home state and those with large progressive populations. 

Buoyed by racially diverse populations in the southeast and blue collar suburban communities in the northeast, Sec. Clinton swept seven states and in turn took commanding lead of the delegate count, which for Democrats includes the state’s pledged electors and so-called “super delegates,” party officials who may support a candidate of their choosing. Super delegates, according to Democratic party rules, are legally unbound and may support any candidate at their own discretion, whether that conflicts with the majority view of their state or even an earlier endorsement.

The Democratic Road Ahead 

To secure the Democratic nomination, 2,383 delegates are required . After Tuesday’s elections, Clinton had won 544 state delegates, almost a quarter of what’s required, and Sanders had won 349. When super delegates are included, Clinton leads Sanders 1,001 to 371, according to a delegate tally by The New York Times.

Clinton’s lead Wednesday over Sanders in the delegate count, at nearly three-to-one, is wider than the lead then-Senator Barack Obama had over her at this point in the 2008 contest.

November 2016

Short of a fundamental reshuffling of the race (and the electorate), the November presidential ballot may well feature the names of two New Yorkers: Donald Trump and Hillary Clinton.