Michigan voters have sent a clear warning to the White House that Joe Biden's support for Israel's war in Gaza could cost him dearly in the presidential election in November.
Activists encouraged people voting in Tuesday's Democratic primary to withhold their votes from President Biden and instead mark the box marked "uncommitted" as a protest. More than 100,000 voters did just that.
The protest vote - while a sharp rebuke - poses no immediate danger to Mr Biden, who still won the contest with 81% of the vote. He's the incumbent president and has no serious challenger from within his party, so he can't lose the race to choose the Democratic candidate.
But what if all the people who withheld their support from him this time don't come out to vote for him in the general election? That could be decisive.
Every vote counts in a key swing state that the US president almost certainly needs to win to have a shot at a second term. In 2016, for example, Hillary Clinton lost Michigan to Donald Trump by fewer than 11,000 ballots.
Mr Trump, following his own victory in the Republican primary, declared: "We win Michigan, we win the whole thing."
This Midwestern state is home to America's largest Arab-American population, most of whom are deeply upset by the devastation they see in Gaza.
President Biden can't afford to ignore their demands that he call for a permanent ceasefire in Gaza - rather than the temporary one that the White House has been pushing for. He did not mention the war or the protest vote in his statement following his victory, but his campaign team will have surely heard the message loud and clear.
