State Sen. Roger Katz, a lawyer and moderate Republican from Augusta who has sometimes clashed with Gov. Paul LePage, says presidential candidate Donald Trump “is not fit to be president” and that he can’t see how Republicans can continue to support him.

In an op-ed first published on pressherald.com Friday, a day after Trump held a rally in Portland, Katz laid out why he believes supporting the New York businessman would be bad for Republicans. The former assistant Senate Republican leader is the highest-profile member of his party in Maine to say Trump will not have his support.

“Considering a Trump presidency shouldn’t be about party loyalty or political ideology,” he wrote. “Instead, it’s become a question of who we are – and who we want to be as Americans.”

Katz, who is Jewish, drew a parallel between Hitler’s rise in Nazi Germany and Trump’s own fear-based rhetoric. He said Trump has seized on the anxieties of Americans and has given them someone to blame: outsiders.

“What Donald Trump has done, in a most calculated way, is to empower others to come out of the woodwork and spew their own dark vision of America,” Katz wrote. “He has appealed to and encouraged the worst of our collective instincts. This is not ‘telling it like it is’ – it is giving permission to others to legitimize bigotry, racism and hate.”

While not naming names, Katz also called out “some nationally prominent Republicans” for condemning some of Trump’s words and actions but still endorsing him or “reserving final judgment to see if ‘he can get back on message’ or ‘stop making these mistakes.’

“I just don’t understand that,” he wrote. “What they are really saying is that Trump will have their support if he will just agree to listen to his handlers, stop speaking his true feelings, and stick to the teleprompter. That makes no sense to me – as if a disciplined speech can whitewash his vitriol. By now, we all know who Donald Trump is.”

U.S. Sen. Susan Collins, Maine’s most prominent Republican, is among those who have called out Trump regularly on specific remarks but have stopped short of saying they can’t support him.

U.S. Rep. Bruce Poliquin, a Republican from the 2nd District, has repeatedly avoided answering questions about Trump.

LePage, who previously backed New Jersey Gov. Chris Christie, said he now supports Trump “more than ever” while introducing the candidate Thursday in Portland.

LePage and Katz have had a strained relationship for the last few years, with the governor blaming him and other Senate Republicans for blocking his efforts to change government.

Prominent Maine Republicans are likely to continue to be asked about Trump between now and November. Former U.S. Sen. William Cohen, who also served as secretary of defense under a Democrat, Bill Clinton, has sharply criticized Trump recently in his role as a political commentator for the BBC.

“I have found very little, if anything, that I could find supporting him as a commander-in-chief,” Cohen said this week.