The War in Gaza Turned This Longtime Michigan Democrat Against Biden

Tucked down in Terry Ahwal’s basement is her personal wall of fame: Here she is at the Obama White House Christmas party. Here is a framed thank-you note from President Bill Clinton. There she is grinning alongside Jennifer Granholm, the former governor of Michigan.

President Biden, Ms. Ahwal says, will not appear on her wall.

After a lifetime of work in Democratic politics — running local campaigns, asking strangers for money, begging acquaintances to vote for candidates — she is now campaigning against the Democrat in the White House.

A Palestinian American who emigrated from the West Bank more than 50 years ago, Ms. Ahwal is furious over the president’s alliance with Israel in its war against Hamas that has killed tens of thousands of Palestinians in Gaza. She does not even have a better candidate in mind, but she vows there is nothing Mr. Biden can do to get her back now.

“You want my vote? You cannot kill my people in my name. As simple as that,” she said recently, sitting at the dining room table of her home in Farmington Hills, a Detroit suburb. Photographs of her travels to Jordan, Peru and the Great Lakes decorate her walls. “Everything Israel wants, they get.”

Such promises to punish Mr. Biden in November have the power to reshape American politics — if they hold. Michigan is home to 200,000 Arab Americans, and other crucial battlegrounds have smaller, but sizable populations. While there are no firm estimates of how many are registered voters, even modest numbers of defection from Democrats could spell trouble for the president’s re-election campaign. Mr. Biden won Michigan by 154,000 voters in 2020. Donald J. Trump won the state in 2016 by 10,700.

There is no shortage of fury and disappointment directed at Mr.