Donald Trump suffered his third electoral setback in a matter of weeks after Democrat John Bel Edwards was re-elected as governor of Louisiana.
Mr Edwards secured his place as the lone Democrat governor in the Deep South despite intense campaigning from the US president, who visited the state on several occasions.
The Republican defeat came within days of the party losing the gubernatorial race in Kentucky where the incumbent, Matt Bevin, was ousted by Democrat, Andy Beshear, by a wafer-thin margin of just over 5,000 votes.
Republicans also lost control of the Virginia legislature, leaving the Democrats in full control of the state’s government for the first time in a generation.
The results in Kentucky, Louisiana and Virginia are likely to alarm GOP strategists, suggesting that Mr Trump is losing support in the suburbs, which are seen as pivotal in next November’s presidential election.
A similar trend was noticed in other local elections, including on the outskirts of Philadelphia - in the key swing state of Pennsylvania.
In Louisiana, Mr Trump had thrown his full weight behind Eddie Rispone, a businessman who had campaigned on the president’s record in the Oval Office.
Mr Trump had made little secret of the national importance of the race as he appealed to Louisiana’s voters for support at a rally last week.
“You’ve got to give me a big win, OK?” he told his audience.
But voters stayed loyal to Mr Edwards, a moderate Democrat, who had distanced himself from the party’s progressive wing as he sought re-election.
Despite the GOP’s defeat in the election, few believe that Mr Trump is in danger of losing the state, which he won by 20 points in 2016, next November.
The results capped what had been a difficult week for the president with fresh allegations of misconduct emerging from the impeachment hearings in Congress.
Democrats maintain Mr Trump abused his power by putting pressure on the newly-elected Ukrainian president Volodymyr Zelenskiy to open an investigation into Hunter Biden, the son of Joe Biden, the former vice president and Mr Trump's potential 2020 opponent.
Leading Democrats have described the testimony from career State Department officials as damning, while Republicans have sought to play down their significance or dismiss the evidence as part of an “establishment coup”.
Early polls suggest that voters remain split on whether Mr Trump should be impeached.
A Reuters/Ipsos poll taken on Thursday and Friday showed that 44 per cent of voters supported Mr Trump’s impeachment - one per cent down on the previous week, while 40 per cent opposed his removal.
Meanwhile, the big winner in the race to be the Democrat candidate next November last week was Pete Buttigieg, the mayor of South Bend, Indiana.
A CNN poll put him nine points clear in Iowa, which will be the first state to pick a candidate when the Democrat caucus meets on February 3.
With Joe Biden’s campaign faltering, Mr Buttigieg - who was virtually unknown at the start of the race - is emerging as Democrat moderates’ best hope of heading off the left-wing Massachusetts senator, Elizabeth Warren.