WASHINGTON: Americans voted on Tuesday to decide whether Donald Trump’s Republicans maintain their grip on the US Congress, or if Democrats can slow the president’s agenda after a divisive campaign marked by clashes over race, immigration and trade.

The first national elections since Trump captured the White House in a stunning 2016 upset is a referendum on the polarizing president and a test of whether Democrats can turn the energy of the liberal anti-Trump resistance into victories at the ballot box.

The Democrats have a good chance of winning at least the US House of Representatives and slimmer hopes of gaining control of the Senate, opinion polls show.

If they do take the House, Democrats could launch congressional investigations into aspects of Trump’s administration from his tax returns to possible conflicts of interest, challenge his overtures to Saudi Arabia, Russia and North Korea, and oppose him on immigration, tax cuts and trade.

If Republicans hold onto both chambers of Congress, Trump likely would claim vindication for his polarizing style, a month after he secured a conservative majority on the Supreme Court when the Senate approved nominee Brett Kavanaugh after a fight over sexual misconduct accusations that split the nation.

Striking a dark tone at a rally in Indiana on Monday evening, Trump accused Democrats of “openly encouraging millions of illegal aliens to break our laws, violate our borders and overrun our country.”

All 435 seats in the House, 35 Senate seats and 36 governorships are up for grabs in elections focused on dozens of competitive races that opinion polls show could go either way.

Democrats are favoured by election forecasters to pick up the minimum of 23 House seats they need for a majority.

The first polling stations close at 6 p.m. Eastern time (2300 GMT) with early results expected shortly after but a full picture likely will not begin to emerge until late at night.

Republicans are expected to retain their slight majority in the Senate, currently at two seats, which would let them retain the power to approve US Supreme Court and other judicial nominations.

US stocks ticked higher in thin trading on Tuesday, as investors awaited the election results.

Political gridlock between the White House and Congress could hinder Trump’s pro-business agenda and raise concerns about US political instability, but investors may have already priced this in.

Analysts expect pressure on stocks if Democrats gain control of the House and a sharper downward reaction if they win the Senate, too. If Republicans hold their ground, stocks could gain further, with hopes of more tax cuts ahead.

‘RACIST’ CONTROVERSY

In a last-minute controversy, NBC, Fox News and Facebook on Monday pulled an ad by Trump’s campaign that critics have labelled racist. The spot featured courtroom video of an illegal immigrant from Mexico convicted in the 2014 killings of two police officers, juxtaposed with scenes of migrants headed through Mexico.

Critics, including members of Trump’s own party, have condemned the commercial as racially divisive. CNN had already refused to run the ad, saying it was racist.

Voter turnout in national elections, normally lower when the White House is not at stake, could be the highest for a midterm election in 50 years, experts predicted. About 40 million early votes were likely cast, said Michael McDonald, a professor at the University of Florida who tracks the figures. In the last such congressional elections in 2014, there were 27.5 million early votes.

“I have worked at this poll the last three elections and this is the biggest turnout ever,” said Bev Heidgerken, 67, a volunteer at a polling place in Davenport, Iowa. “We usually hope for 200 voters for the entire day but by 9 o’clock we already have had 69.”

There were sparse reports of voting technology failures on Tuesday and they appeared so far to have had no significant impact in preventing people from voting, a Department of Homeland Security official said.—Reuters