The day before Donald Trump’s Chicago fundraiser, Dan Webb, a prominent Republican and former U.S. attorney, urged Republicans on Monday to vote for and contribute to Democrat Hillary Clinton.

“I think there are a huge volume of Republicans who are saying the thing I am saying,” Webb told the Chicago Sun-Times, that Trump “is not fit to be president.”

“But they are sitting on the sidelines, and I urge some of them to get off the sidelines, give Hillary some money and support her because we can’t afford to let him become president,” Webb said.

Trump hits Chicago on Tuesday for a high-dollar fundraising lunch. The minimum contribution is $10,000, and the tab is $100,000 for the “VIP roundtable.”

Democrats are planning two demonstrations: one at Trump Tower, 401 N. Wabash, and another across the river from the tower, a site selected so the cameras will have the giant Trump Tower letters in the background of the shot, an organizer told the Sun-Times.

One of the Trump protests is organized by NextGen Climate Illinois, a spinoff of the NextGen national organization running an independent expenditure campaign against Trump. The other demonstration was put together by a coalition of Democratic-allied groups in coordination with the Democratic National Committee. Coordinated campaign and independent expenditure groups cannot legally work together.

Hope Hicks, Trump’s spokeswoman, told the Sun-Times that Trump has no other Chicago events and he will not have any media availability.

Webb’s public split with the presumptive GOP presidential nominee is emblematic of Trump’s campaign, continuing to struggle to unify Republicans, even as the kickoff of the GOP convention in Cleveland on Monday is fast approaching.

At the same time, Democrats are moving toward unification as Bernie Sanders, after an agreement was struck on the party platform and other related policy issues, endorses Clinton on Tuesday at an event in Portsmouth, New Hampshire.

While the top Illinois Republican elected officials, Sen. Mark Kirk, R-Ill., and Gov. Bruce Rauner, are not supporting Trump — Kirk called him an “Eastern, privileged, wealthy bully” last week — they have not gone so far as to declare they will vote for Clinton. Kirk, who withdrew his one-time backing for Trump, has been saying he will write-in former CIA director David Petraeus.

Webb, the co-chairman of Winston & Strawn, was tapped by President Ronald Reagan, a Republican, to be the U.S. Attorney for the Northern District of Illinois in the 1980s. Webb has long been associated with Republicans, even though he has at times donated to some Democrats.

At the presidential level, however, when Webb casts a vote for Clinton, it will be his first to put a Democrat in the White House. He has contributed $5,400 directly to the Clinton campaign and has given a sum to a Clinton-associated super PAC.

Webb said he first became concerned about Trump because of his “bias” against Hispanics, Muslims and women, and his attack on U.S. Federal Court Judge Gonzalo Curiel, born in East Chicago, Indiana, the son of Mexican immigrants. Trump said Curiel could not fairly preside over the Trump University fraud lawsuits on his docket because Trump wants to build a wall between the U.S. and Mexico.

Webb called Trump’s comments about Curiel “despicable,” adding, “if you are running for president of the United States, you shouldn’t be talking about your own personal cases, let alone be attacking a judge.

“. . . That pulled me over to decide I couldn’t sit it out, that I think Republicans have to stand up and once and for all at least for one campaign, make it clear that he cannot be allowed to be president of the United States,” Webb said.

Kent Gray, who was the Trump state director for Illinois and Missouri before the March primaries, said Webb’s position is “unfortunate because next week is going to be a unifying event for Republicans supporting Mr. Trump.”

Webb said Republicans like him — in the private sector who don’t have to worry about elections — have to “get off our butts and financially support her and get out of the closet because there are enough of us to swing this election.”

Clinton will be in Illinois on Wednesday for an event in Springfield and a high-dollar fundraiser in Wilmette.