WASHINGTON — Democrats clinched two more years of controlling the House on Tuesday but with a potentially razor-thin majority, a bittersweet finale to last week's elections that has left them divided and with scant margin for error for advancing their agenda.

The party has now nailed down at least 218 seats, according to The Associated Press, and could win a few others when more votes are counted. While that assures command of the 435-member chamber, blindsided Democrats were all but certain to see their current 232-seat majority shrink after an unforeseen surge of Republican voters transformed expected gains of perhaps 15 seats into losses potentially approaching that amount.

"We have the gavel, we have the gavel," said House Speaker Nancy Pelosi, D-Calif., who seems all but certain to continue in that role. While she bemoaned Democrats' losses in districts where GOP votes proved "almost insurmountable," she told reporters last week, "We've lost some battles but we've won the war."

By retaining the House, Democrats will control the chamber for four consecutive years for only the second time since 1995, when Republicans ended 40 years of Democratic dominance.

Yet though Joe Biden won the presidential election, there was a strong chance Republicans would keep Senate control. That would force Democrats to scale back their dreams of sweeping health care, infrastructure and other initiatives, instead needing compromises with the GOP.

As the bad news sunk in, Rep. Cheri Bustos, D-Ill., who led House Democrats' campaign committee, announced Monday she wouldn't seek another term leading that organization. Democrats said privately she would have lost had she again sought the post, for which the party's lawmakers vote.

Republicans have been heartened by the House results, which many believe position them for a strong run for the majority in the 2022 elections. They also bolstered their distressingly low number of women representatives from 13 to at least 26, a record for the GOP, according to the Center for American Women and Politics at Rutgers University, and were adding new ethnic minority lawmakers as well.

"The Republican coalition is bigger, more diverse, more energetic than ever before," House Minority Leader Kevin McCarthy, R-Calif., said the day after the election.

Democrats went into Election Day with a 232-197 House advantage, plus an independent and five open seats. With some races remaining undecided, it was possible that in the new Congress that convenes in January they'll have the smallest majority since Republicans had just 221 seats two decades ago.

Democrats secured the majority after The Associated Press declared three winners late Tuesday: incumbents Kim Schrier in Washington, Tom O'Halleran in Arizona and Jimmy Gomez in California.

A tight majority could cause headaches for Pelosi, empowering any determined group of lawmakers to pressure her on what bills should be considered or look like. But sometimes, a slender margin can help unify a party because its members know they must stick together to achieve anything.

Democratic moderates and progressives clash periodically, and while the moderates are more numerous, the progressives' ranks include influential social media stars like Rep. Alexandria Ocasio-Cortez, D-N.Y.

Underscoring that tension, House Democrats vented during a three-hour conference call last week in which both factions blamed the other for rhetoric and policies they said proved costly in the campaign.

"We should be honest that this was not a good outcome," Rep. Tom Malinowski, D-N.J., a moderate freshman, said in an interview. He said terms like "defunding the police" hurt Democrats by making it sound like they oppose law enforcement, and said they shouldn't speak "as if we were talking to woke progressives in neighborhoods where 90% of the votes are for Democrats."

Rep. Pramila Jayapal, D-Wash., a progressive leader, said in an interview that Democrats need to discuss "how we talk about some of these issues that are critical to different parts of our base." But with moderates complaining that the GOP hurt Democrats by repeatedly accusing them of pushing socialism, Jayapal said such accusations "will be used against us no matter what we say."

Democrats believed they'd pick up seats, especially in suburbs, because of a decisive fundraising edge, President Donald Trump's unpopularity and exasperation over the pandemic. Many Republicans and independent polls supported that expectation.

But with some races still uncalled, Democrats haven't defeated a single GOP incumbent and failed to capture open GOP-held seats in Texas, Missouri and Indiana they thought they'd win.

Instead, they've lost at least seven incumbents: six freshmen from states including Florida, Oklahoma and South Carolina plus 30-year veteran Rep. Collin Peterson from rural Minnesota. And while they successfully defended most of their 29 districts that Trump carried in his 2016 victory, they saw stronger than expected performances by GOP candidates all around the country.

"With President Trump on the ballot, it just drove enormous turnout that was almost impossible to surmount," said Rep. Elissa Slotkin, D-Mich., a reelected freshman.

" The country has become more polarized and divided," said Rep. Gerald Connolly, D-Va. "If you're running in alien territory, you're always at risk of failure."

So far, Democrats' only pickups were three open seats from which Republicans retired. Two were in North Carolina, where court-ordered remapping made the districts strongly Democratic, and one was outside Atlanta.

Going into the election, Democrats envisioned strengthening their moderate wing, since most districts they seemed likely to capture were closely divided between GOP and Democratic voters. But they ended up suffering losses in those same type of districts, meaning it was mostly moderates who lost.

"In electoral politics, moderates are the beachfront property," said Jim Kessler, an official with Third Way, a centrist Democratic group. "And if there's flooding, they're the ones that get washed away."

Illustrating that, the Blue Dog Coalition of the most conservative House Democrats, whose membership has dwindled in recent years, lost at least six of its roughly two dozen members.

On the other hand, a handful of hard-left progressive freshmen will be coming to Congress, including Democrats Jamaal Bowman and Mondaire Jones of New York and Cori Bush of Missouri, who each won seats in overwhelmingly blue districts.

On the Republican side, the conservative House Freedom Caucus was hoping to grow from its roughly 30 members.

The group has tried pushing GOP leaders to the right over the years and was a consistent source of trouble for the past two Republican speakers, John Boehner of Ohio and Paul Ryan of Wisconsin.