President Joe Biden and former president Donald Trump won the Michigan primaries on Tuesday, further solidifying the all-but-certain rematch between the two.
Mr Biden defeated Minnesota representative Dean Phillips, his one significant opponent left in the Democratic primary.
But Democrats were also closely watching the results of the “uncommitted” vote, as Michigan has become the epicentre for dissatisfied members of Mr Biden’s coalition that propelled him to victory in the state — and nationally — in 2020.
The number of “uncommitted” votes has already surpassed the 10,000-vote margin by which Mr Trump won Michigan in 2016, surpassing a goal set by organisers of this year’s protest effort.
As for Mr Trump, he has now swept the first five states on the Republican primary calendar.
His victory in Michigan over his last major primary challenger, former UN ambassador Nikki Haley, comes after the former president defeated her by 20 percentage points in her home state of South Carolina on Saturday.
The Trump campaign is looking to lock up the 1,215 delegates needed to secure the Republican nomination sometime in mid-March.
Both campaigns are watching Tuesday’s results for more than just whether they won as expected.
For Mr Biden, a large number of voters choosing “uncommitted” could mean he is in significant trouble with parts of the Democratic base in a state he can hardly afford to lose in November.
Mr Trump, meanwhile, has underperformed with suburban voters and people with a college degree, and faces a faction within his own party that believes he broke the law in one or more of the criminal cases against him.
Mr Biden has already sailed to wins in South Carolina, Nevada and New Hampshire.
The New Hampshire victory came via a write-in campaign as Mr Biden did not formally appear on the ballot after the state broke the national party rules by going ahead of South Carolina, which had been designated to go first among the Democratic nominating contests.
Both the White House and Biden campaign officials have made trips to Michigan in recent weeks to talk with community leaders about the Israel-Hamas war and how Mr Biden has approached the conflict, but those leaders, along with organisers of the “uncommitted” effort, have been undeterred.
The robust grassroots effort, which has been encouraging voters to select “uncommitted” as a way to register objections to his handling of Israel’s ongoing war in Gaza, has been Mr Biden’s most significant political challenge in the early contests.
That push, which began in earnest just a few weeks ago, has been backed by officials such as Democratic representative Rashida Tlaib, the first Palestinian American woman in Congress, and former representative Andy Levin.
Our Revolution, the organising group once tied to senator Bernie Sanders, had also urged progressive voters to choose “uncommitted” on Tuesday, saying it would send a message to Mr Biden to “change course NOW on Gaza or else risk losing Michigan to Trump in November”.
Mr Trump’s dominance of the early states is unparalleled since 1976, when Iowa and New Hampshire began their tradition of holding the first nominating contests.
He has won resounding support from most pockets of the Republican voting base, including evangelical voters, conservatives and those who live in rural areas. But Mr Trump has struggled with college-educated voters, losing that bloc in South Carolina to Haley on Saturday night.
Mrs Haley has vowed to continue her campaign through at least Super Tuesday on March 5, pointing to a not-insignificant swath of Republican primary voters who have continued to support her despite Mr Trump’s tightening grip.
She also outraised Mr Trump’s primary campaign committee by almost 3 million dollars in January. That indicates that some donors continue to look at Mrs Haley, despite her longshot prospects, as an alternative to Mr Trump should his legal problems imperil his chances of becoming the nominee.