WASHINGTON: Pennsylvania voters went to the polls on Tuesday (Mar 13) in a special election widely seen as a major test for President Donald Trump and a Republican Party fighting to maintain its control of the US Congress.
Democrat Conor Lamb, a former federal prosecutor and US Marine officer, has run a surprisingly strong race against Republican state representative Rick Saccone as they battle to fill a vacant congressional seat for District 18, the working-class southwestern corner of the Keystone State.
Turnout appeared to be high for a special election, the Pittsburgh Post-Gazette reported, citing poll workers.
Trump, who won the district by more than 20 points in his 2016 presidential race, endorsed Saccone and made an 11th hour campaign stop with the candidate.
But Lamb's unexpectedly strong performance in Trump country - the race was considered a toss-up going into Tuesday - underscored the challenges that Republicans face as they prepare to defend their majority in both the Senate and House of Representatives in November's all-important mid-term elections.
The party occupying the Oval Office tends to lose seats in the first mid-terms after winning the presidency.
With chaos swirling in the White House, Trump's approval rating under water, and a special prosecutor investigating potential collusion between Trump's campaign and Russia, Democrats are counting on a domino effect at the polls to send them back to power in Congress.
Republican organisations have poured millions of dollars of outside money into the race in the hopes of dragging Saccone across the finish line and signalling that their position ahead of the mid-terms is not as precarious as Democrats suggest.
In District 18, several of Trump's campaign promises have resonated with voters - in particular, his call for restricting immigration, supporting gun rights, and bringing back jobs in the coal and steel industries.
At a Monday rally at Blaine Hill fire department, Saccone took aim at Democrats, portraying them as having "a hatred for our president," "a hatred for our country," and "a hatred for God."
But Lamb, who has played up his blue-collar roots and his support for organized labor, seems to have avoided alienating Trump supporters, and downplayed the idea that the Pennsylvania election is a referendum on the controversial commander in chief.
The district's voters "overwhelmingly want me to work with the president," Lamb said after casting his ballot early on Tuesday.
Trump has described Saccone as "very strong on experience" while painting Lamb as "weak on crime" and border security.
"The economy is raging, at an all time high, and is set to get even better. Jobs and wages up," Trump tweeted on Tuesday.
"Vote for Rick Saccone and keep it going!"
With Trump in Saccone's corner, Democratic former vice president Joe Biden, who was born in Pennsylvania, campaigned with Lamb in the district last week.
"Something's changing out there," Biden tweeted late on Monday. "You can feel the grassroots energy. And that'll beat big money every time."
Lamb is endorsed by the main mineworkers and steelworkers unions in the region, whereas Saccone, 60, has had a tempestuous relationship with organised labor.
The district's previous congressman, Republican Tim Murphy, resigned last year amid an adultery scandal.
Polls were to close on Tuesday at 8.00pm (8.00am Singapore time Wednesday).