The longest-serving Republican in the Iowa Legislature announced Tuesday that he’s becoming a Democrat, saying he didn’t want to remain in a party led by President Trump.

Rep. Andy Mckean, 69, a retired attorney from eastern Iowa city of Anamosa, said he made his decision after returning to the Legislature after years away from politics and finding the Republican Party had changed. He was a registered Republican for nearly a half-century, The Washington Post reported.

During a news conference at the Iowa Statehouse in Des Moines on Tuesday, McKean said if the president’s behavior and leadership is the new normal, “I want no part of it.”

“Unacceptable behavior should be called out for what it is and Americans of all parties should insist on something far better in the leader of their country and the free world,” McKean said.

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McKean first entered the House in 1979 and served seven terms. He left the legislature but returned to the Senate in 1993 and served three terms. He then won election to the House in 2016 and was re-elected in 2018. He has served nearly 29 years in the Legislature.

When he returned, McKean said he disagreed with Republicans on many high-profile issues but declined to comment further.

McKean, who describes himself as a moderate, pointed to Trump’s spending decision and what he called the president’s “erratic, destabilizing foreign policy,” choices regarding the environment and “disregard for the truth.”

The lawmaker said as the 2020 election approached, he believed the country will pay a “heavy price for Trump’s reckless spending and shortsighted financial policies.”

“He sets, in my opinion, a poor example for the nation and particularly for our children by personally insulting, often in a crude and juvenile fashion, those who disagree with him, being a bully at a time when we’re attempting to discourage bullying,” McKean said of Trump.

McKean said he will register as a Democrat when he returns home later this week and plans to seek re-election as a Democrat in 2020.

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It’s rare for Iowa legislators to change parties. The last time it occurred was in 2007 when Rep. Dawn Pettengill, of Mount Auburn, switched from Democrat to Republican.

McKean is not the first Iowa lawmaker to quit the party citing Trump. Former Sen. David Johnson announced he was quitting the party in 2016 as a demonstration to Trump’s presidency, the Des Moines Register reported.

McKean’s decision prompted an angry response from Jeff Kaufmann, the chairman of the state Republican Party.

"When Rep. McKean ran in 2016, he had no problem riding to victory on President Trump's coattails," Kaufmann said. "He's about to feel the headwind of President Trump's support in District 58."

Troy Price, Iowa’s Democratic Party Chairman, welcomed McKean.

"His decision to put people over politics shows his commitment to our state,” Price said of McKean.

The Associated Press contributed to this report.