Longtime Republican Assemblyman Brian Maienschein announced Thursday that he is switching his affiliation to the Democratic party.

“As the Republican Party has drifted further right, I and my votes have shifted to the left,” Maienschein told reporters in Sacramento. “I can either keep fighting to change the Republican party, or I can fight for my constituents.”

He said he is no longer in sync with the national party on gun control, immigration, abortion, LGBTQ rights and many other issues.

Maienschein won re-election to a fourth term in November by just 607 votes amid a Democratic wave that swept California.

“I welcome the addition of Assemblymember Brian Maienschein to the Democratic Party. His legislation, his actions and his presence in the Assembly have always shown him to be a man committed to ideas for making California better, not to ideology that divides us,” said Assembly Speaker Anthony Rendon following Maienschein’s announcement.

Sunday Gover, who was Maienschein’s Democratic opponent in November, said, “Clearly our campaign had a massive impact and it’s good news that Mr. Maienschein has finally left the Republican Party, but simply switching parties doesn’t address the issues our community needs championed in Sacramento.”

Maienschein was one of the last Republicans representing San Diego County in the Assembly, leaving Marie Waldron and Randy Voepel. Waldron termed Maienschein a “turncoat,” and the San Diego County Republican Party called for his immediate resignation.

“Brian Maienschein has shown himself to be the absolute worst kind of politician; someone making decisions based on politics instead of principles,” said Tony Krvaric, chairman of the county party. “By running for re-election as a Republican, he was making a statement about who he was and now he is switching parties for self-preservation and political games.”

Maienschein’s switch further strengthens Democrats’ supermajority in the Assembly, which now totals 61 of the chamber’s 80 seats.

“Leaving the Republican Party is not easy,” he said, but “Donald Trump has led the Republican Party to the extreme on issues that divide our country.”

Maienschein represents the 77th District, which encompasses north inland San Diego, Poway, Rancho Santa Fe and Fairbanks Ranch.

Updated at 3:10 p.m., Thursday, Jan. 24, 2019

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