Congressional leaders anxiously left town Thursday for the five-week march to Election Day with some trying to dial down expectations as they brace for the political fallout from an election that could deliver the narrowest margins on Capitol Hill in at least 15 years.

Senate Majority Leader Mitch McConnell (R-Ky.), with just three seats to spare to retain the GOP’s hold on the chamber, pointed to seven races that are going down to the wire, mostly across Midwest.

“Knock-down drag-out, sort of like a knife fight in a phone booth,” McConnell told reporters at a news conference after Congress concluded its legislative business the day before.

Across the Capitol, House Speaker Paul D. Ryan (R-Wisc.) acknowledged that his side would lose ground from its current 247-member caucus, the largest Republican majority since 1930. He said he does not like “losing any seats” but hinted Republicans would still be in a good position as long as they do not come close to losing the 30 seats that would hand Democrats the majority.

I don’t like the idea of losing any seats,” Ryan said. “I think a good night is keeping our strong majority.”

Democrats expressed confidence at their electoral prospects but they have become more restrained in their optimism as hopes that the controversial campaign being run by Republican presidential nominee Donald J. Trump would lead to major losses for GOP congressional candidates have faded a bit.

Sen. Charles E. Schumer (D-N.Y.), the incoming Democratic leader, pointed at the huge amounts of money from corporate interests pouring into the Senate battleground races that would have otherwise gone toward Trump’s campaign. Industrialists like Charles and David Koch have decided not to support Trump’s bid because they disagree with his protectionist policies and have instead focused on congressional elections.

“I think we will win a majority in the Senate,” Schumer said. “It’s been made closer only because of two words, Koch brothers. Three words — Koch brothers money.” 

And House Minority Whip Steny H. Hoyer (D-Md.) acknowledged that, as of now, the presidential race between Trump and Hillary Clinton has not broken sharply enough in the Democrat’s direction to bring along with her dozens of Democrats to reclaim the House. “It is not beyond the realm of possibility that we take back the House if there’s a wave election created. Right now, we don’t see that,” Hoyer told reporters.

He then predicted “significant” gains of around 20 additional seats.

Such a Democratic victory would fall short of the majority, but it would leave Ryan’s House Republicans hobbled and unsteady. A loss of 20 seats would leave just 227 Republicans in the House, the smallest majority either party has had since 2002.

Independent analysts at the nonpartisan Cook Political Report and Rothenberg & Gonzales Political Report are now predicting more modest gains for Democrats, in the range of 10 to 15 seats. (Stuart Rothenberg, the founder of that report, now writes a column for The Washington Post.)

In recent days House Republicans have grown more confident as Democrats have moved some financial resources away from targeted races in some suburban districts held by the GOP. The Cook report on Thursday moved eight districts into more favorable terrain for Republicans in its analysis of the electoral map.

House Minority Leader Nancy Pelosi (D-Calif.) did not predict a majority, but she did say Trump was the “gift that keeps on giving” for Democrats. She recently predicted a gain of at least 20 seats and suggested the majority could be within reach, but she noted Thursday that it might depend on whether Clinton can open up a significant enough lead to lift down-ballot Democrats.

“I think that we are all in agreement, including Steny, that we’re going to win very many seats,” Pelosi said. “And some of it, as he said, depends on how big the margin is for Hillary Clinton.”

In the Senate, Democrats stand to gain between three and six seats, according to the Rothenberg & Gonzales report. A three-seat gain would leave them just short of the majority, by one seat, and a four-seat gain would leave the chamber evenly divided at 50-50 for only the second time in the last 60 years.

In a 50-50 scenario, the winner of the presidency would claim the Senate as his or her vice president would then serve as the president of the chamber. The last evenly divided Senate came in the opening months of 2001, as Republicans held the majority — and the committee chairman’s gavels — because Richard Cheney served as the GOP vice president.