WASHINGTON – Democrats seized control of the House in the 2018 midterm elections, ending unified Republican rule of Washington and setting the stage for confrontation with President Donald Trump when they take power in January.

Democrats are expected to leverage their new majority to wield Congress' oversight powers. They could demand Trump’s tax returns, subpoena his Cabinet members and investigate suspected ties to Russia. And they can block the president’s legislative priorities, whether it’s funding for a wall along the U.S.-Mexico border or curbing entitlement programs.

Democrats notched key wins in suburban districts from Virginia to Colorado to Florida, standing as a rebuke to Trump. Although the final party breakdown remained in flux as of Wednesday morning, Democrats were expected to win more than the 23 seats they need to gain control.

With 218 seats needed for a majority, Democrats have won 219 and the Republicans 193, with winners undetermined in 23 races.

House Democratic Leader Nancy Pelosi told reporters on Capitol Hill Wednesday that women candidates led the party's charge and that the issue of health care, specifically the requirement that insurers cover those with pre-existing conditions, secured their win.

“Health care was on the ballot and health care won,” Pelosi said.

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The new Democratic majority would work to lower the price of prescription drugs, invest in infrastructure and reduce the role of "dark, special-interest money" in politics, she said.

She promised oversight of the Trump administration but did not commit to investigations, saying that would be the province of committee chairs. However, she specifically noted the committees that would find topics worthy of inquiry, including Judiciary, Intelligence and especially Homeland Security.

The country should be "shamed," Pelosi said, about the policy that separated immigrant children from their mothers.

A leading Democratic antagonist of Trump, Rep. Adam Schiff, is poised to take over the House Intelligence Committee. He told MSNBC Tuesday night that the panel under Republicans had "completely abdicated" its oversight of the White House.

Another Democrat on the Intelligence Committee, Eric Swalwell, outlined hearings he expected to be held.

“We'll fill in the gaps on the Russia investigations," Swalwell told NBC News. "The American people will see his tax returns, not because of any voyeuristic interest, but because they should know if he is corrupt. And we will look at the cashing in of access to the Oval Office and that has been concerning, and his financial entanglements overseas.”

Trump lashed back Wednesday, threatening to investigate Democrats.

Trump also offered support for Pelosi to regain the House Speaker's gavel, although he may simply prefer her as a liberal foil to attack.

Later Wednesday, Trump said at a news conference he was sincere in his praise of Pelosi and could work with her on issues like health care.

"I give her a great deal of credit for what she's done and what she has accomplished," Trump said. "Hopefully we can all work together to deliver for the American people."

For defeated Republicans, Rep. Jim Jordan of Ohio, a conservative ally of Trump, announced Wednesday his bid to lead the party in the House.

Outgoing House Speaker Paul Ryan congratulated Democrats for taking the House and Republicans for solidifying their hold on the Senate. He noted the headwinds facing the party in power during midterm election.

"We don't need to have an election to know that we are a divided nation, and now we have a divided Washington," the Wisconsin Republican said in statement tweeted by his spokeswoman.

Female candidates spearheaded Democratic gains. At least 80 women had been elected to the House. Sixty-nine of the House women are Democrats, including 27 of 28 newcomers, according to a USA TODAY analysis.

In Virginia, Democrat Jennifer Wexton, a state senator, toppled incumbent GOP Rep. Barbara Comstock. Wexton held a more than 12% lead over Comstock with more than 99% of ballots counted. Comstock, branded "Trumpstock" by Wexton in ads, fell short in a well-to-do suburban district that has become increasingly Democratic.

In Colorado, incumbent GOP Rep. Mike Coffman lost to Democrat Jason Crow, a lawyer and combat veteran. In Florida, Democrats knocked off incumbent GOP Rep. Carlos Curbelo and snagged an open seat held by longtime incumbent GOP Rep. Ileana Ros-Lehtinen, who is retiring.

In suburban Philadelphia, Democrat Mary Gay Scanlon was declared the winner in another open seat held by former GOP Rep. Pat Meehan, who resigned amid questions about accusations of misconduct toward a junior female staffer. Scanlon, a former school board member and attorney, also benefited from a court-ordered redistricting decision that made the district significantly more Democratic. She defeated former Republican prosecutor Pearl Kim in November.

GOP Rep. Pete Sessions, whose district includes the wealthy Dallas suburbs, lost to Colin Allred, a civil rights attorney and former player for the NFL’s Tennessee Titans in Texas’ 32nd District. Sessions is chairman of the powerful Rules Committee and led the National Republican Congressional Committee when it made historic gains in 2010. He had not faced a competitive race in years.

While many of the Republicans who were knocked off were centrists, a handful of conservatives in GOP districts once thought to be safe found they would not be returning to Washington next year.

In Virginia’s 7th Congressional District, Democratic former CIA officer Abigail Spanberger scored a major upset, ousting conservative GOP Rep. Dave Brat in a race that was surprisingly competitive for a district that has been reliably red. Brat knows about upsets: In 2014, he defeated then-GOP Majority Leader Eric Cantor in the Republican primary. President Donald Trump carried the district by 7 percentage points in 2016.

Democrats gained a seat in Iowa’s 1st Congressional District, a blue-collar swing seat now represented by arch conservative GOP Rep. Rod Blum and carried by Trump by 3 percentage points in 2016. Democrat Abby Finkenauer, a 29-year-old state representative, is slated to become the first woman ever elected to the House from Iowa.

Rep. Claudia Tenney fell to Anthony Brindisi, a New York state assemblyman, in New York’s 22nd District. Tenney had aligned herself closely with the president, who won the district by more than 15 points in 2016.

There was at least one pickup for Republicans. Minnesota’s 8th District elected Republican Pete Stauber, a retired police commander, former professional hockey player and county commissioner. He beat Democrat Joe Radinovich, who served in the Minnesota House. (In Minnesota, the Democrats are the Democratic-Farmer-Labor (DFL) Party.)

Two indicted Republicans, Californian Duncan Hunter and New York state’s Chris Collins, won their re-election bids.

Hunter and his wife, Margaret, face a 60-count federal indictment alleging conspiracy, wire fraud and misspending and falsification of campaign finance records. Collins is accused of insider trading. Party leaders asked him to withdraw, but he stayed in the race.

Republicans fended off stiff challenges in some more conservative districts. In Kentucky, GOP Rep. Andy Barr defeated Democrat and former Marine fighter pilot Amy McGrath. The district, which includes Lexington and Frankfurt, shouldn’t have been competitive: Trump won it by 15 percentage points in 2016. But McGrath turned it into a tight race, attracting national attention with viral TV ads, including one that showcased her 89 combat missions. The Associated Press declared Barr the winner.