In House races, Democrats scored some early victories Tuesday in their quest to wrest control of the chamber, but Republicans were holding on in some key races where they faced strong challengers as initial returns were tallied in the first midterm election of Donald Trump’s presidency.

Republicans entered Tuesday with strong prospects of keeping their Senate majority but the victory by GOP challenger Mike Braun over Senator Joe Donnelly in Indiana and Republican Marsha Blackburn’s win in Tennessee made it much more difficult for Democrats to make inroads.

Democrats would have to win every other competitive Senate race to defy what were already long-shot odds of winning a majority in the chamber.

In one of the first key House races to be called, Democrat Jennifer Wexton scored a victory for her party by defeating incumbent GOP Representative Barbara Comstock in a suburban Virginia district that had been was considered a bellwether by both parties.

But in some other tossup races, the GOP managed to hold on. Republican incumbent Andy Barr fended off a strong challenged from Democrat Amy McGrath, a Naval Academy graduate and the first female Marine to pilot an F/A-18 Hornet in combat, in Kentucky’s 6th Congressional District. Still, she was within striking distance in a Lexington-area district Trump won by 15 percentage points in 2016.

In Virginia’s 7th District, a Republican-leaning area near Richmond, Republican Representative Dave Brat was in a tight race with Democrat Abigail Spanberger, a former CIA officer.

Those House races, along with several others in states where polls had closed, were being watched for insights into whether Trump can push forward with his agenda unimpeded or find himself restrained by a Democratic-controlled House.

Senator Bob Menendez of New Jersey beat Republican challenger Bob Hugin to win a third term. The incumbent was reprimanded by a Senate ethics panel after corruption charges were dismissed following a mistrial, turning a what should have been a sure bet for Democrats into a close fight.

Trump’s polarizing impact on the country has driven unusually high interest in the election, the first major political test of his presidency and one that will provide Democrats with clues to the strategy they’ll need to challenge him in 2020. The flood of political donations from interest groups and individuals will make it the most expensive midterm ever, and early signs suggest voter turnout could be the highest in half a century.

In Florida, six House seats are in play, and there are close and crucial battles for a Senate seat and the governorship.

While the occupant of the White House is typically central to midterm elections, Trump has worked especially hard to make this one about him. Voters agree. Two-thirds of those casting ballots said their vote was about Trump, according to preliminary exit polls posted by CNN. Also, more said they showed up at the polls to express opposition than did those who said they were casting a ballot to support him.

“As president, Donald J. Trump has headlined an unprecedented 50 rallies — 30 in the last two months alone — and he has campaigned for dozens of candidates at all levels of government,” White House Press Secretary Sarah Sanders said in a statement Tuesday evening. “The president has energized a staggering number of Americans at packed arenas and in overflow crowds at rallies across the country.”

Preliminary exit poll results reported by ABC News showed that 18- to 29-year-olds accounted for 13 percent of voters nationally, up from 11 percent in 2014. About 15 percent said that this was the first time they’d voted in a midterm, according to CNN, compared to about 10 percent who said they were first-time voters in the 2016 election. That could help Democrats because younger voters tend to lean their way.

After a hectic week of campaigning, Trump spent Tuesday at the White House awaiting exit polls and final results. He was active on Twitter throughout much of the day, blasting out endorsements for Republican candidates and weighing in on the balloting.

Congressional Roadblock

If Democrats manage to win the House of Representatives, Trump would be left without congressional support to move his agenda forward. The party has pledged to check the president’s power and start a slew of investigations on matters including his tax returns, Russian involvement in the 2016 election and actions by his administration.

Democrats have expressed confidence that they’ll score the net gain of 23 seats needed to take control of the House for the first time since 2010. While Republicans confront serious headwinds in holding the House, the uniqueness of the contest in each of 435 House districts makes for a wide range in the potential number of seats Democrats may gain.

House Democratic leader Nancy Pelosi said her party had momentum on its side.

“We’re going to win, based on data,” Pelosi of California said at the Democratic campaign headquarters in Washington. “Do not let their scare tactics frighten you away from the polls.”

Senate Control

Both sides agree, at least privately, that Republicans are strongly favored to keep control of the Senate, where the electoral map is highly favorable to them. In both Senate and House races, Democrats have focused heavily on health care and protecting people with pre-existing medical conditions.

About four in 10 voters choose health care as the most important issue facing the country, and seven in 10 say the nation’s health-care system needs major changes, the exit polling shows. About two in 10 each choose the economy and immigration as their top issue, and just one in 10 say it’s gun policy.

Fifty-eight of voters said the country is headed in the wrong direction, compared with 41 percent who said it is on the right track, according to a nationwide survey conducted in all 50 states for The Associated Press and Fox News. The survey is separate from the traditional exit polls for the television networks.

Trump and Republicans appeared to have the economy on their side heading into the election: Unemployment in October held at a 48-year low of 3.7 percent.

Fernando Rivera, a 53-year-old small-business owner in Miami, said he voted for all Republicans because he wants Congress to support Trump and his economic policies. He said since Trump has been president, he ’s hired two more employees for his six-person company.

“Trump is improving the economy — that’s the most important thing for me,” Rivera said. “Now we just need to heal the country so they can all work together.”

President’s Focus

He deployed more than 5,000 troops to the border and suggested he may triple that number. His campaign team created an advertisement focused on the caravan that was so racially charged that major TV networks pulled it.

The president’s strategy of emphasizing divisive issues risks backfiring on Republican candidates in suburban swing districts that probably will determine control of the House. Yet it may be effective in largely rural states where he remains popular and where many of the closest Senate races are playing out.

The campaign will be the most expensive midterm in history, projected by the nonpartisan Center for Responsive Politics to exceed $5 billion.

Other records were also falling. At least 255 women were on the ballot as major party congressional candidates. The total number of women serving simultaneously may exceed 100 for the first time. DM