That’s not to say feeling upbeat comes naturally to Democrats. Or as Missouri Democratic Rep. Emanuel Cleaver put it: “Every time I get too happy I slap myself and stick my hand over a fire.”

“I’m a nervous ninny,” Cleaver added. “I read the polls … but I’m scared to feel like we’re going to win because we’ve seen what happened in 2016.”

Sure enough, Democrats’ talking points are filled with bromides about taking nothing for granted and working all the way through Election Day, after Trump’s shocking win across just enough swing states to take the Electoral College four years ago. But beneath the surface, there’s growing confidence among key Democrats that things are actually going to go their way this time.

Trump is an unpopular incumbent saddled with a recession and an out-of-control coronavirus pandemic that has killed more than 220,000 Americans. Meanwhile Biden has only seen his favorability ratings increase over time, emerging largely unscathed from Trump’s attacks on him and his son Hunter Biden. And Biden is outspending Trump down the homestretch almost everywhere, further boxing in Trump's path to 270 electoral votes.

Several states that were once considered reaches for Democrats look viable and Midwestern battleground states have generally given Biden a durable lead, fueling a rare good mood in the party known for handwringing.

“There has been a lot more consistency and a lot less volatility to the polling in 2020 than 2016. Joe Biden has had a 4-5 point lead since I think May,” said Sen. Tammy Baldwin (D-Wis.), who handily won reelection in 2018.

"Four years ago at this point I told people that Hillary was going to lose Michigan, I knew it in my gut. Now I think Michigan is competitive," said Rep. Debbie Dingell (D-Mich.).

Democrats still face some uncertainty. Trump was less volatile during Thursday evening’s debate and Biden potentially cost himself some votes in key energy-producing states during the last clash of the night. Trump seized on Biden’s comments that he would “transition” away from the oil industry before the former vice president clarified he meant he’d stop giving them federal subsidies if elected.

Still, Biden’s comments had Republicans breathing easier about their prospects for holding the Senate and limiting House losses. Sen. Lindsey Graham (R-S.C.), himself facing a competitive race, said “the president helped all of us that are running in 2020."

“He was more focused on trying to get his points across and willing to let Biden talk. And if it could have lasted longer Biden may have said more things like, ‘I’m going to eliminate the oil industry,’” said Sen. Roy Blunt (R-Mo.).

Democrats said the low bar set for Trump by his own party is not one shared by Americans. Sen. Chris Coons (D-Del.) said Trump wasn’t as “belligerent or unsettling,” but that the debate was not the game changer the GOP needs at this late stage.

“This was Trump’s last chance to change the trajectory of the race. And he gained no benefit from last night,” Coons said.

In fact, confidence is increasing so much in the party that red state Democrats are joining in. Sen. Joe Manchin (D-W.Va.) said he would be “shocked” if Trump won this time. Trump carried his state by 42 points in 2016, but appears struggling to rebuild that level of support in the Mountain State.

“If Joe Biden gets over 40 percent [in West Virginia] it’s a victory. I think President Trump has worn everybody out,” Manchin said. He claimed even his GOP colleagues are exhausted with the president: “It would be a true relief to my friends on the Republican side” if he loses.

“It feels different” than 2016, agreed Sen. Elizabeth Warren (D-Mass.). “It feels like there’s more urgency now. People have had four years of Trump. And he is so much worse than people expected he would be.”

Still, not every Democrat is ready to crow about a possible Biden victory. Several lawmakers said they’re still reeling from the shock of 2016, when party leaders on down were boasting about a Clinton win only to be blindsided by the FBI’s decision to reopen its investigation into the former secretary of state’s email server just days before the election.

Trump allies have tried to recreate the “October surprise” in relation to Biden and his son’s past work in Ukraine, but with little success so far. Still, Democrats are on edge as so many of the variables that could swing the election — from the record number of mail-in ballots expected to interference efforts by Russia and other foreign adversaries — remain out of their control.

"I’m trying to remain as calm as I can, and not euphoric," Rep. John Yarmuth (D-Ky.) said, pointing to Biden's momentum in the polls and the enthusiasm he's seeing in the local get-out-the-vote effort. The one sign that gives him pause, he said, is the GOP voter registration numbers in key battleground states such as Florida and Pennsylvania.

“All leads seem to be holding up. I’m just trying to remember how confident I was in 2016 and stopping myself from getting back in the place,” said Sen. Chris Murphy (D-Conn.). “There’s a lot of reasons to feel this is different. But I’m nervous.”

Other Democrats were even more blunt in their assessment, saying they won’t feel any sense of relief until the polls close on Nov. 3. Moderate Democratic Rep. Henry Cuellar of Texas was in New York at the Clinton election night party four years ago, preparing to celebrate a landslide victory.

Now some of his fellow Texas Democrats are openly musing about the long-shot chance Biden has at winning the reliably red state if he sweeps the country. Cuellar, though, is not ready to go there because “Trump has a way that you just can’t rule him out.”

“I’ve fundraised for the party, for the Biden campaign, I'm doing extra — putting more money here to make sure he wins my congressional district. People feel good, but again, we've seen this before,” Cuellar said.

Montana Sen. Jon Tester was even more direct in his advice for fellow Democrats: “Run through the f---ing tape.”

Sarah Ferris contributed to this report.