Muslim voters once abandoned the GOP. Now they may leave the Democrats.

Arab and Muslim voters moved away from the Democratic Party this year in ways that led some community leaders to warn of a lasting shift from a voting bloc that has been reliably Democratic for two decades since it abandoned the GOP.

While no single group proved to be the difference maker in Tuesday’s election that President-elect Donald Trump won by a comfortable margin, the outcome shows another group of voters of color trending toward Trump despite his rhetoric about them.

“We may see a mass exodus of multigenerational Democrats from the party,” said Layla Elabed, the co-chair of the national Uncommitted movement, which sprang up during the Democratic primaries to protest President Joe Biden’s support for Israel’s war in Gaza. “If the Democratic Party does not move in a way that is more aligned with their base, there’s going to be real long-term repercussions.”

Muslim Democratic operatives swapped stories of parents or aunts and uncles voting Republican or third party for the first time in their lives and now worry they may not get them back.

Muslim voters backed Republican George W. Bush in 2000, but fled the GOP in response to the Bush administration’s post-9/11 military interventions abroad and anti-terror policies at home, which they felt unfairly targeted people of Islamic faith.

In the two decades since then, Muslim Americans have broken roughly 2-to-1 for Democrats, while groups representing the community institutionally aligned themselves with Democrats, much like other groups representing voters of color.

The Democratic Party seemed like an especially natural place for Muslims in the Trump era, as he banned people entering the country from predominately Muslim nations after a failed attempt to ban believers of the faith outright and he expressed views considered Islamophobic.

But on Tuesday, Trump won the most Arab American city in the country, Dearborn, Michigan, while Green Party nominee Jill Stein, who campaigned on ending what she has called a genocide in Gaza, took a far larger share than she won elsewhere.

Trump won 42% of the vote — a nearly 15 percentage-point gain from 2020 — in Dearborn, where more than half of residents are of Middle Eastern descent. Harris, meanwhile, received just 36% in the city, barely more than half of Biden’s 2020 vote share. Stein received 18% of the vote, compared to less than 1% nationwide.

The result was nearly identical in neighboring Dearborn Heights, also home to a large Middle Eastern community, where Mayor Bill Bazzi endorsed Trump last month.

Nationally, the Council on American-Islamic Relations, one of the largest Muslim advocacy groups in the country, which has been sharply critical of Biden’s foreign policy, conducted its own postelection survey of Muslim voters. Just 20% of respondents said they backed Harris, compared to 69% who said they backed Biden in CAIR’s 2020 exit poll.

“Our final exit poll of American Muslim voters confirms that opposition to the Biden administration’s support for the war on Gaza played a crucial role, leading to a sharp drop in support for Vice President Harris,” said CAIR National Government Affairs Director Robert S. McCaw.

Muslim and Arab Democrats say their party never took seriously the anger felt by their community. Indeed, many Democrats assumed Arab and Muslim voters would come back into the fold, reluctantly or not, once it became clear to them that Trump might win and give Israeli Prime Minister Benjamin Netanyahu free rein.

“So, Dearborn delivered for Trump? OK, congratulations. You’re going to love the next Muslim ban,” Sen. John Fetterman, D-Pa., said in a postelection interview that rocketed around group chats of Arab Democrats, who said it was emblematic of the dismissive way they felt their concerns were treated.

Beyond the strategic blunder, they say Harris’ campaign failed tactically to do the 101-level politics of constituency management in their community — showing up at meetings, courting leaders and providing face time with the candidate.

“Day after day, for well over a year, we warned President Biden and Vice President Harris,” said Rania Batrice, a Palestinian American Democratic strategist. “Our pleas, demands and warnings were ignored by President Biden and then by Vice President Harris. My hope is that as Democrats do their post-mortem on this cycle, they reflect on whether they’re content with the fact that almost every swing, statewide race went to Democrats, and they’ll learn that we are not the party of the Cheneys.”

Trump actually spent more time courting local religious and community leaders in the Dearborn area than Harris. He held a roundtable and photo-op with imams, invited Arab politicians who endorsed him to speak onstage at his rallies, and dispatched Tiffany Trump’s father-in-law, a Lebanese-born businessman, to wine and dine community leaders.

“Our efforts in mobilizing the community demonstrated that Muslim Americans are no longer taken for granted. Trump has acknowledged our role, and we are ready to work alongside his administration to advocate for policies that support peace and unity,” said Rabiul Chowdhury, a co-founder of Muslims for Trump, which was active in Pennsylvania, Michigan and Wisconsin.

The Uncommitted movement, which sent 30 delegates to the Democratic National Convention, offered to endorse Harris in exchange for having a speaker to address the plight of Palestinians, but that request was rebuffed.

Arab and Muslim Democratic leaders say the rejection of even that symbolic gesture made it difficult to convince their community that Harris and the Democratic Party cared about them. The Harris campaign acknowledged that it was counting on a surge in support from the suburbs to swamp any losses in places like Dearborn.

“We tried to warn people,” said Georgia state Rep. Ruwa Romman, a Palestinian American Democrat who was an Uncommitted delegate. “I feel like people thought we were just making it up for attention.”

Still, Democrats are hardly ready to write off the demographic and are hoping Tuesday’s result was the product of a specific moment and can therefore be changed in the future.

Abdullah Hammoud, the Democratic mayor of Dearborn, who refused to endorse Harris, said the results show neither party should take his community’s support for granted.

“While political pundits analyze the outcomes, here is what I know,” he said on X. “Votes are never promised to any party or candidate.”

This article was originally published on NBCNews.com