Joe Biden told a room of donors and lobbyists on Monday that Republicans “know better” and suggested that the GOP would be open to cooperation at the end of Donald Trump’s presidency ― comments seemingly contradicted by the party’s eight years of lockstep opposition during Barack Obama’s two terms.

“Here’s the deal: we all know, and I don’t think this is hyperbole, we all know in our gut this election is the most important election we’ve ever engaged in ― and not just because I’m running,” the former vice president said at an event in Washington.

Biden, who is leading a crowded pack of Democrats hoping to unseat Trump next year, issued a terse warning to those gathered at the event, telling supporters that four years of Trump would merely be an “aberration,” but anything longer would be devastating.

“Eight years of Donald Trump will fundamentally change who we are in profound ways,” Biden said, according to a pool report. He later said change was possible in Congress, noting: “With Trump gone you’re going to begin to see things change. Because these folks know better. They know this isn’t what they’re supposed to be doing.”

Biden supported his claim by saying that 12 former Republican colleagues in the Senate expressed concerns about the party’s blockade of Obama’s Supreme Court nominee, Merrick Garland (the Garland episode predated Trump’s presidency).

It’s not the first time Biden has touted the return of bipartisanship. Last month, the longtime lawmaker alluded that many in the GOP had become intimidated by Trump during his administration, but said he anticipated an “epiphany among many of my Republican friends” in the future.

″[T]he thing that will fundamentally change things is with Donald Trump out of the White House. Not a joke,” Biden said at an event in New Hampshire in May. “It’s already beginning ― in the House now, you’ve seen people that in fact were not willing to vote for any Democratic initiative, even if they agreed with it, because they didn’t want to be the odd person out if it wasn’t going to happen.”

While campaigning for reelection in 2012, Obama predicted that if he won a second term, the “Republican fever may break.” He added: “My hope, my expectation, is that after the election, now that it turns out that the goal of beating Obama doesn’t make much sense because I’m not running again, that we can start getting some cooperation again.”

The fever never broke. Instead, it intensified, culminating in 2016 with Republicans’ nomination of the man who once led the birther movement against Obama.

With 23 Democrats already in the race, the hits on each other have already begun. Biden has had some significant stumbles in recent weeks and his challengers have begun to criticize the former vice president as part of the old guard in Washington who may be too centrist to unseat Trump and counter his vast base of support.

Biden on Monday warned that prolonged party infighting would only increase the “chances that this fella (Trump) will win.“

“Everybody knows who Donald Trump is,” Biden said. “We gotta let them know who we are and who I am.”

The first Democratic debates begin later this month.