Rep. Andy McKean, Iowa’s longest-serving Republican lawmaker, left his party on Tuesday to join the Democrats, and cited President Donald Trump as a factor in his decision.

“With the 2020 presidential election looming on the horizon, I feel, as a Republican, that I need to be able to support the standard bearer of our party,” McKean told reporters at the Iowa Capitol during a news conference on Tuesday. “Unfortunately, that’s something I’m unable to do.”

McKean named several behaviors by Trump that he said were “unacceptable.”

“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 are attempting to discourage bullying, his frequent disregard for the truth and his willingness to ridicule or marginalize people for their appearance, ethnicity or disability,” he said.

He added: “I believe that his actions have coarsened political discourse, have resulted in unprecedented divisiveness, and have created an atmosphere that is a breeding ground for hateful rhetoric and actions. Some would excuse this behavior as telling it like it is and the new normal. If this is the new normal, I want no part of it.”

McKean, who served seven terms in Iowa’s house after being elected in 1978, then three terms in the senate before retiring in 2006, rejoined the house in 2016 and returned to a very different political atmosphere than the one he’d been accustomed to. “I found myself increasingly uncomfortable with the stance of my party on the vast majority of high profile issues and often sympathetic with concerns raised by the minority caucus,” he said.

McKean’s exit puts him among other state Republican legislators in suburban districts who have left the party in recent years.

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Write to Mahita Gajanan at mahita.gajanan@time.com.