AP Photo House Minority Leader Nancy Pelosi of Calif., center, speaks between two of her grandsons and Congressional Democrats as they celebrate Democratic wins in the House of Representatives to a crowd of Democratic supporters during an election night returns event at the Hyatt Regency Hotel, on Tuesday, Nov. 6, 2018, in Washington. At left of her grandson is House Minority Whip Steny Hoyer, D-Maryland.

WASHINGTON (AP) — Democrats were gaining significant ground in the battle for House control Tuesday night, while Republicans held their Senate majority as voters rendered a mixed verdict in the first nationwide election of Donald Trump’s turbulent presidency.

The results allowed both parties to claim partial victory, but highlighted an extraordinary realignment of U.S. voters by race, sex and education. Republicans maintained their strength in conservative, rural states, while Democrats made inroads across America’s suburbs.

With control of Congress, statehouses and the president’s agenda at stake, some of the nation’s top elections were too close to call.

Yet Democrats’ dreams of the Senate majority as part of a “blue wave” were shattered after losses in Indiana, Tennessee, North Dakota and Texas. They also suffered a stinging loss in Florida, where Trump-backed Republican Ron DeSantis ended Democrat Andrew Gillum’s bid to become the state’s first African-American governor.

In the broader fight for control in the Trump era, the political and practical stakes on Tuesday were sky high.

Democrats could derail Trump’s legislative agenda for the next two years should they win control of the House. And they would claim subpoena power to investigate Trump’s personal and professional shortcomings.

Some Democrats have already vowed to force the release of his tax returns. Others have pledged to pursue impeachment, although removal from office is unlikely so long as the GOP controls the Senate.

Democrats won half the seats they needed to claim House control with dozens additional competitive contests remaining. Victories in contested races across Florida, New York, Virginia, Pennsylvania and Minnesota gave them cause for optimism. Trump sought to take credit for retaining the GOP’s Senate majority, even as the party’s foothold in the more competitive House battlefield appeared to be slipping.

“Tremendous success tonight. Thank you to all!” Trump tweeted.

History was working against the president in the Senate: 2002 was the only midterm election in the past three decades when the party holding the White House gained Senate seats.

Nearly 40 percent of voters cast their ballots to express opposition to the president, according to AP VoteCast, the national survey of the electorate, while one-in-four said they voted to express support for Trump.

Overall, 6 in 10 voters said the country was headed in the wrong direction, but roughly that same number described the national economy as excellent or good. Twenty-five percent described health care and immigration as the most important issues in the election.

Nearly two-thirds said Trump was a reason for their vote.

Democrats performed well in the race for the House, a sprawling battlefield set largely in America’s suburbs where more educated and affluent voters in both parties have soured on Trump.

Democrats’ chances were always considered weak in the Senate, where they were almost exclusively on defense in rural states where Trump remains popular.