Casino magnate Sheldon Adelson, a GOP mega-donor and staunch Israel-backer, is among a number of Republican groups and donors who spent large amounts in the last presidential cycle in 2012 but are wavering or steering clear of supporting Republican nominee Donald Trump, according to a report in the Guardian on Saturday.

For now, according to the report, their funding is instead going to congressional races, amid fears of the Republicans losing control of the House because of Trump’s weak poll numbers and repeated gaffes and controversies.

The GOP nominee has been trailing behind Democratic rival Hillary Clinton in poll after poll, plagued by charges of anti-Semitism, racism and running a divisive, hate-driven campaign. Clinton recently accused Trump of popularizing prejudice in a manner unprecedented in modern American history.

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Many Republican donors and fundraisers worry that a Trump defeat to Clinton would have a disastrous effect on Republican House representatives and senators come Election Day.

Adelson, according to a source who spoke to the Guardian, is “irked by a lot of things,” including that the nominee did not make a visit that Adelson wanted him to make to Israel, and that Trump chose Mike Pence as his vice presidential candidate. Adelson reportedly wanted House Speaker Newt Gingrich.

Adelson and Trump are said to have met privately a number of times this year.

On a recent visit to New York, Adelson reportedly met with South Carolina senator Lindsey Graham to discuss “the financial needs of senators in tough races.” It was not clear if Adelson met Trump on that same trip.

Adelson had endorsed Trump earlier this summer, indicating he would contribute some $100 million to his run. But Adelson has reportedly yet to contribute significant sums to Trump’s campaign through Super Pacs. One senior Republican told the Guardian that he was “shocked that Adelson has not done anything yet for Trump. Sheldon knows that late money is wasted.”

Two GOP sources told the Guardian that Adelson had given $10 million to One Nation, a group run by a former top aide to Senate majority leader Mitch McConnell. The group is legally able to keep its donors secret and has spent some $16 million this year on Senate run ads.

Trump representatives have refused to confirm or deny the contribution.

Trump recently overhauled his campaign leadership staff, following a number of controversies, including a public tiff with the family of Muslim army captain killed in Iraq in 2004, a threat to stop raising money for the Republican party, and a refusal to run any television ads even as his opponents fill the airwaves with spots backing Clinton in several contested states.

Trump also drew Republican ire when he refused to endorse House Speaker Paul Ryan, Arizona Sen. John McCain and Ohio Gov. John Kasich John McCain, a former presidential rival, in the GOP primary, later reversing his position this month.