A prominent Democrat and Jewish leader who served for decades as a New York lawmaker and now leads a group committed to fighting antisemitism announced Thursday he's leaving his lifelong political party and becoming a Republican, arguing Democrats have become "radicalized" and "turned their back" on the Jewish people.

"It's official: My wife and I have switched our party affiliation from Democrat to Republican!" Dov Hikind, who spent 36 years in the New York State Assembly and later founded Americans Against Antisemitism, tweeted.

"[People] have long been asking, 'Dov, when are you gonna leave the Democratic Party?' Well, the time has come [because] the Dems have turned their back on Jews & Israel, so it's officially done!"

Hikind's tweet included a video of him and his wife, Shani, explaining their decision to join the Republican Party.

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"I have been a lifelong Democrat — my family, my parents. But that's over. That's finished," said Hikind. "I have decided to register as a Republican. Unfortunately, the Democratic Party has become so radicalized … that people who are moderates or conservative Democrats are not welcomed in the Democratic Party, and I've had enough."

Hikind added the Democratic Party "turns its back on its friends like Israel," criticizing the Biden administration for its policies toward the Jewish state.

"I am delighted to join the Republican Party," Hikind added. "This is about sending a message — a message to the Biden administration, a message to the Democratic Party. We're losing the American people because you are not representing our values. You are not representing the Democratic Party that my parents were so proud of."

Hikind's announcement came one day after some progressive Democrats boycotted a speech by Israeli President Isaac Herzog, who addressed a joint meeting of Congress to mark the 75th anniversary of Israel's founding. During his speech, Herzog gave a thinly veiled rebuke to members of the House for recent attacks on Israel.

"Criticism of Israel must not cross the line into negation of the state of Israel's right to exist," said Herzog. "Questioning the Jewish people's right to self-determination is not legitimate diplomacy. It is antisemitism. Vilifying and attacking Jews, whether in Israel, in the United States or anywhere in the world, is antisemitism."

Over the weekend, Progressive Caucus Chair Pramila Jayapal, D-Wash., caused an uproar by calling Israel a "racist state." Though she walked back her comments somewhat, they were still met with fierce criticism from both sides of the aisle.

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The furor led Republicans to force a vote on a resolution that said Israel was neither a racist nor an apartheid state. The measure was overwhelmingly supported by all but ten Democrats — nine who voted "no" and one who simply voted "present." Jayapal voted with the majority that said Israel was not racist.

On Thursday, the same day as Hikind's announcement, Rep. Alexandria Ocasio-Cortez, D-N.Y, doubled down on calling Israel an "apartheid" state.

Hikind is hardly the first former or current Democrat lawmaker to recently switch parties.

Earlier this month, Mesha Mainor, a Democrat who has represented District 56 in the Georgia House since January 2021, announced she will switch her party registration to Republican.

"When I decided to stand up on behalf of disadvantaged children in support of school choice, my Democrat colleagues didn’t stand by me," Mainor told Fox News Digital at the time. "They crucified me. When I decided to stand up in support of safe communities and refused to support efforts to defund the police, they didn't back me. They abandoned me."

In April, state Rep. Jeremy LaCombe announced he had left the Democratic Party and would be registering as a Republican. At the time, he was the second Louisiana Democrat in less than a month to switch party affiliations after Louisiana state Rep. Francis Thompson gave Republicans in the state House a supermajority by switching his party affiliation.

The "modern-day Democratic Party has become unrecognizable to me and others across the state," North Carolina State Rep. Tricia Cotham said of her decision to switch parties. "I will not be controlled by anyone."

Overall, more than one million Americans have switched their party affiliation from Democrat to Republican in the last 12 months.