President Joe Biden and former President Donald Trump won their respective parties’ primaries in Michigan on Tuesday.

Biden overcame an activist-led push to lodge protest votes over his response to Israel’s war with Hamas, although the effort was at roughly 13% of the vote shortly after midnight.

Biden is barreling toward the Democratic nomination for a second term, while the former president is heading toward securing the GOP nod for the third straight election.

Trump’s win further shuts the door on former South Carolina Gov. Nikki Haley’s hopes of building momentum ahead of next week’s Super Tuesday contests, when more than one-third of the party’s delegates are at stake.

While Biden easily won the Democratic race, the results carried some warning signs for the president. He faced organized resistance led by Arab and Muslim Americans, as anger over the administration’s handling of Israel’s war in Gaza sparked a campaign to convince Democratic voters to cast protest ballots for “uncommitted.”

The effort, called “Listen to Michigan,” was endorsed by Michigan Rep. Rashida Tlaib and former Rep. Andy Levin, and backed by progressive groups such as Our Revolution, the organization spun out of Vermont Sen. Bernie Sanders’ 2016 presidential bid. (Sanders had no part in that decision, according to a spokesperson, and is supporting Biden.)

Even as the votes were still being counted Tuesday night, organizers of the Michigan group deemed their campaign a success.

“We demand President Biden to take action now – bring a permanent ceasefire,” said Layla Elabed, the campaign manager for the group. “A vote uncommitted was a humanitarian vote.”

She said the effort was just beginning, with plans to keep pressure on the president alive in the eight months until the November election.

“I want to thank every Michigander who made their voice heard today. Exercising the right to vote and participating in our democracy is what makes America great,” Biden said in a statement on the primary results that took aim at Trump and did not acknowledge the uncommitted movement.

The Michigan primary was moved up near the front of the Democratic presidential nominating calendar this year. With Biden’s encouragement, party officials demoted Iowa and New Hampshire from their traditional spots on the calendar in hopes of building a more diverse lineup of early voting states, which typically command attention and winnow the party’s field of contenders.

Michigan is also among the most important presidential swing states — and one that helped deliver Trump the White House in 2016 after a nearly 11,000-vote win there. Biden defeated Trump in Michigan by about 150,000 votes four years later.

Activists sought to send Biden a message about the political costs of his support for Israel in a must-win state. Dearborn, in particular, is home to one of the largest Arab American communities in the United States.

In 2020, nearly 146,000 Muslim Americans voted in the general election in Michigan, according to an analysis by Emgage, a group working to grow Muslim Americans’ political power.

“This is not an anti-Biden campaign,” Elabed, Palestinian American, recently told CNN. “It’s a humanitarian vote. It’s a protest vote. It is a vote that tells Biden and his administration that we believe in saving lives.”

Biden, meanwhile, has put political muscle into Michigan — where the Democratic governor, Gretchen Whitmer, was on his 2020 vice presidential short list and won reelection easily in a 2022 race in which her support for abortion rights played a central role.

The president walked the picket line with the United Auto Workers union in Michigan in September during a strike against major auto manufacturers. “You deserve what you’ve earned, and you’ve earned a hell of a lot more than you’re getting paid,” he said then. The UAW endorsed Biden in January.

Trump inches closer to third straight nomination

Trump celebrated his primary win with a call to the Michigan GOP watch party in which he looked forward to a likely rematch against Biden.

“We win Michigan, we win the whole thing,” the former president said, according to a transcript provided by the Trump campaign.

The Michigan GOP primary was the first of two contests this week that will award the state’s 2024 presidential delegates. Trump is favored to rack up more delegates Saturday, when the Michigan GOP gathers for a convention.

The split contests to award delegates are the result of Republicans’ reaction to Democrats’ decision to shake up their party’s presidential nominating calendar after the 2020 election — demoting Iowa and New Hampshire, moving South Carolina and Nevada to the forefront, and placing Michigan third in the new lineup.

Michigan Republicans opposed the earlier state primary as it violated Republican National Committee rules limiting which states can hold contests before March 1. After Democrats, who control the state Legislature and the governor’s office, moved the Michigan primary to February 27 despite the Republican opposition, the RNC and Michigan GOP came up with the hybrid model.

As a result, 16 of Michigan’s 55 delegates were at stake in Tuesday’s primary and will be awarded proportionally based on the result. The other 39 will be awarded at Saturday’s convention — three to the preferred candidate of the delegation from each of the state’s 13 congressional districts.

Further complicating matters: The Michigan GOP is in the middle of a battle over who leads the party, with two people who claim the mantle of party chair holding dueling conventions Saturday.

The RNC and Trump have recognized Pete Hoekstra, a former congressman and US ambassador to the Netherlands, as chair. However, Kristina Karamo, the election conspiracy theorist whom the state party voted to oust in January, has refused to relinquish control — arguing that she was unlawfully removed. A Michigan court on Tuesday affirmed her removal as state party chair.

Hoekstra has scheduled a Saturday convention in Grand Rapids. But Karamo is also holding a convention in Detroit. The RNC’s decision to recognize Hoekstra signaled that the party would accept delegates from the convention he will oversee.

This story has been updated with additional information.

CNN’s Arit John, Dianne Gallagher, Jeff Zeleny and Kate Sullivan contributed to this report.