An obsession over President Donald Trump among some Establishment Republican circles threatens to sink the entire party in November, conservative leaders warned Thursday on Fox News’ “The Ingraham Angle.”

On paper, the Senate offers an opportunity for Republicans to pick up seats, with Democratic incumbents’ seeking re-election in states that Trump won by double digits in 2016.

But the GOP could not only let those chances fall through the cracks. It could actually also lose control of the upper chamber if infighting prevents a strong turnout for vulnerable Republican incumbents such as Dean Heller of Nevada (pictured above left) and Ted Cruz of Texas (pictured above right).

“We all know the anti-Trump base is coming out,” said Ari Fleischer, who served as White House press secretary under George W. Bush. “Like it or not, this is a nationalized election. There’s no dodging it, and the Trump base needs to show up in presidential year numbers, not off-year numbers.”

David Bossie, president of the activist group Citizens United, said Democrats never seem to let party squabbles divide them when to comes to general elections.

“The Left is always good at standing together, no matter awkward it may be,” he told host Laura Ingraham on the Fox News show. “Look, the Republicans really need to — they have 54 days to decide whether or not they want to continue to have control of the House and of the Senate.”

Bossie criticized Republican leaders including Sens. Jeff Flake of Arizona and Bob Corker of Tennessee for never seeming to miss a chance to knock Trump, even though neither is seeking re-election due to their unpopularity back home.

“Trump Derangement Syndrome amongst some of these Republicans is really unfortunate,” he said. “Look, Flake and Corker should be out there campaigning for candidates across their states and across the country. And instead, they’re not. They’re out there attacking this president and undermining his great policy positions, these great economic numbers that we have.”

Fleischer agreed.

“Why do they have to keep stirring this pot?” he asked. “You know, I understand how the press can put a microphone in front of a politician and say, ‘Will you say something anti-Trump?’ and they run to do it. It’s not constructive.”

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Fleischer that his old White House boss traditionally has stayed off the campaign trail since leaving office.

“But his popularity is rising,” he said “And frankly, Laura, I want to see more Establishment Republicans out there helping our candidates everywhere. This is about the future of our nation.”

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Former Republican National Committee Chairman Reince Priebus, who was Trump’s first White House chief of staff, told Ingraham he believes Bush should campaign for Cruz in his home state.

“Control of the Senate is what’s at stake. You let bygones be bygones,” he said. “Win control of the Senate, not just for the president, but if you’re not willing to work for the president, work for the good of the country and the things you believe in as a Republican — period.”

Added Bossie: “President Trump is not on the ballot in November, but his policies are. The ‘America First’ agenda that he ran on and won on and has made America great again over the last 18 months is on the ballot this November, and we have to show up in force.”