WASHINGTON — Sen. John Fetterman (D-Pa.) is threatening to leave the Democratic Party if it becomes overtly anti-Israel.

In a series of interviews with reporters this week, Fetterman has pointed to anti-Israel sentiment among Democratic primary candidates and strong Democratic support for a House amendment banning aid to Israel as reasons he could leave the party.

But Fetterman told HuffPost he’d only actually leave the party if Democrats “make it official” in the party platform “and say we will never support aid for Israel.”

Many of the 103 House Democrats who voted for the amendment on Wednesday, which would have cut off aid to the country and which ultimately failed, said their support reflected frustration with Israeli Prime Minister Benjamin Netanyahu and his deadly war in Gaza, not the concept of Israel itself.

“That’s why I’m still a Democrat,” Fetterman said Thursday.

Democrats won’t write an official new party platform until 2028, by which point Fetterman could be on his way out of office. Polling indicates he could be especially vulnerable to a primary challenge: Just 19% of Democrats in a Quinnipiac University poll released Wednesday approved of his job performance, while 69% disapprove.

A full 52% of voters, including majorities of both Democrats and Republicans, said they hoped Fetterman would leave the Democratic Party. That would not necessarily make his path to reelection any easier: a three-way race as an independent would be difficult to win, and his high level of support among Republicans would be difficult to maintain against a more consistently conservative candidate.

Fetterman, at this point, seems to spend more time with Republicans than Democrats. He and the other senator from Pennsylvania, Republican Dave McCormick, recently opened a highly unusual bipartisan joint fundraising committee.

It’s also unclear if Fetterman will even run for reelection: After suffering a stroke during his bid for Senate, he has battled mental health issues in the years since. And after breaking with the progressive wing of the Democratic Party over his support for Israel, he has sharply limited his in-state travel.

Fetterman’s tension with his fellow Democrats isn’t new. In recent weeks he’s been especially vexed by the party’s rallying around Graham Platner, the progressive Senate candidate in Maine whose campaign imploded in a sexual assault scandal following a series of red flags about Platner’s judgment.

Before Platner flamed out, Fetterman wondered, sort of like how he has this week, if the Democratic Party would formally adopt what he didn’t like as part of its platform.

“Have we become the pro-dick party?” Fetterman asked reporters in the Senate basement in June.

Fetterman pivoted to Platner on Thursday in response to questions about Israel. He seemed to resent the attention he’s received and noted that his victory over Dr. Mehmet Oz in the 2022 Pennsylvania Senate election has helped put Democrats in striking distance of recapturing the Senate majority in this fall’s midterms.

“Why is it outrageous as a Democrat to call Platner the piece of shit that he’s always been? I mean, like this isn’t radical ideas here,” he said. “You know, I made the math possible for a majority in ’26. The people that pushed that garbage now just made that now more unlikely.”

While the party’s relationship with Israel has unquestionably become more negative in recent years, key parts of party leadership are still supportive of the country and closely tied to AIPAC. House Democratic Leader Hakeem Jeffries (D-N.Y.) called for an “urgent change” to the U.S.-Israel relationship in a letter to his colleagues this week, but emphasized support for Israel’s right to exist and the standard two-state approach that’s long been part of the U.S.-Israel partnership.

“I laid out the position I believe we as House Democrats will take as we move forward, anchored in several different principles, including our support for Israel’s right to exist as the homeland for the Jewish people, and at the same time pressing the urgent need to establish an independent Palestinian state that allows the Palestinian people to live with dignity, respect and self-determination,” Jeffries said Thursday.