Meanwhile, US President Donald Trump considers the midterm election results to be a success amid projections that Democrats will take control of the US House of Representatives and the Republicans will maintain a majority in the US Senate.
But the Democrats appear to have won control of the House of Representatives with more than two-thirds of seats declared.
A major surge in early voting also sparked speculation that the so-called "Trump effect" was motivating progressive voters to turn out in record numbers - but as numerous election experts have pointed out, early voting has been a rising trend for years, and it's unclear whether all those early voters support Republicans or Democrats.
The newly empowered House Democrats will have the ability to investigate Trump's tax returns, possible business conflicts of interest and allegations involving his 2016 campaign's links to Russian Federation.
It is common for the midterms to go poorly for the party with an incumbent President, but losing the House will still come as a huge blow to Trump, after campaigning relentlessly over the past couple of months. Moscow denies meddling and Trump denies any collusion.
She says Democrats will find common ground when they can and stand their ground when necessary.
Trump called the results a "tremendous success", while House Democrat minority leader Nancy Pelosi said "tomorrow will be a new day in America".
Tuesday's result was a bitter outcome for Trump, a 72-year-old former reality TV star and businessman-turned-politician, after a campaign that became a referendum on his leadership. He finished his final midterm campaign stretch on Monday with three rallies.
The White House has been stressing the historical headwinds it faced: In the last three decades, 2002 was the only midterm election when the party in office gained Senate seats.
Ariana Grande Shades Pete Davidson for ‘SNL’ Engagement Joke
She was able to express this side of her story through most of the songs, which are included in her newest album Sweetener . Ariana , 25, and Pete, 24, decided that it simply "wasn't the right time" for them to be together, a source claimed to TMZ .
Democrats were gaining speed in their quest for the House, which would give them the ability to launch investigations into the president and stymie his agenda. For presidents with approval ratings below 50%, like Trump, the average loss was 37 House seats. Polls in other key states including Florida, Pennsylvania and New Jersey closed at 8 p.m. EST.
Republicans paved their path to victory by defeating Democrats Joe Donnelly of IN and Heidi Heitkamp of North Dakota.
Democrats landed on a plan to allow each vulnerable Democrat to run an independent campaign without a unified platform.
Former vice president Joe Biden, often touted as a possible Democratic candidate to take on Trump in 2020, said he'd have been "dumbfounded" not to win the House. Andrew Gillum lost to Republican Ron DeSantis in his quest to become Florida's first black governor. Two Democratic women veterans with viral web videos - MJ Hegar in Texas Amy McGrath in Kentucky - lost their races in traditionally Republican districts. Democrat state legislator Laura Kelly will be that state's next governor.
Republicans banked on those dynamics being offset by a vibrant economy and by a president whose insult-laden approach to political discourse was as stirring for conservative voters as it was infuriating to liberals. But, depending on the margin of victory for Democrats in the House, even that is unlikely to be immune to partisan obstruction.
In the Senate, the Republicans had the 51 seats needed for control, while in the House of Representatives, the Democrats had passed the 218 they needed and had 219 seats. Perhaps more important, they would claim subpoena power to investigate Trump's personal and professional shortcomings. The father of four, with a fifth on the way, worries that Republicans will get rid of the Affordable Care Act if they remain in control of Congress.
Democratic Rep. Jerrold Nadler, who is slated to steer the House Judiciary Committee warned that the election was about accountability for Trump.
Investors often favour Washington gridlock because it preserves the status quo and reduces uncertainty, even though many investors this time around had been hoping for a continuation of the Republican agenda.
The nationwide survey indicated that almost two-thirds said Trump was a reason for their vote.