Democrats were gaining significant ground in the battle for House control Tuesday night, while Republicans held onto their majority in the Senate as voters weighed in on the first nationwide election in Donald Trump's turbulent presidency.
The Republicans are on course to increase their representation from 51 to 54 in the 100-seat Senate upper chamber.
Trump's personal income taxes, which he withheld during the 2016 campaign and in his two years in office, are expected to be the purview of the House Ways and Means Committee.
A Republican governorship majority coupled with GOP victories in gubernatorial races in battleground states may also boost Trump in 2020, since governors hold veto power over redistricting measures.
The election served as a referendum of sorts on Trump's racially charged appeals and the strength of the coalition that powered him to the White House - a group he will need again in just two years.
"I think that I am better at that game then they are actually", he said.
"Or we can work together", he said, adding that "it really could be a attractive bipartisan type of situation".
He decried, as he often has for months, special counsel Robert Mueller's ongoing investigation into Trump 2016 campaign links to Russian Federation and whether Trump, as president, obstructed justice by trying to thwart the investigation. "They ignored the consultants who said they should cover up their tattoos and smile more, and they ignored the powerful men of the Republican Party who never took them seriously anyway".
Trump reeled off a shopping list of disadvantages he claimed that the Republicans had faced going into Tuesday's vote, including "wealthy donors and special interests" for the Democrats, and "very hostile media coverage".
At one point during the press conference, a visibly angry Trump branded CNN's White House correspondent Jim Acosta a "rude, awful person" and an "enemy of the people" in a testy exchange.
"I didn't say it prevented me, I said lawyers will tell you not to do it", he said. "When you report fake news, which CNN does a lot, you are the enemy of the people".
Almost 40 per cent 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.
Dems are on track to gain 11 House seats in these states including California, a state where the GOP didn't even have a Senate candidate on the statewide ballot this year.
Democrats will pick up between seven to nine House seats in this region, and while they came up short in the Iowa governor's race, they now control three of the four House seats there.
It's unclear what powers Mr Trump might use to block the release of these filings, as the White House is not supposed to be part of the decision-making process that was set forth in the 1924 law that gives lawmakers the ability to demand the release of any tax return.
Any investigation of the president is likely to face the same fate as that of the Russian Federation investigation by special counsel Robert Mueller.
"Nobody turns over a (tax) return when it's under audit", Mr Trump said during a news conference when asked about the returns.
Mr Trump also said that if Democrats began using their new majority to investigate him, he would direct Senate Republicans to launch investigations targeting Democrats. Democrats relied more upon women, people of colour, young people and college graduates. The president endorsed Nancy Pelosi to be the speaker of the House and said that the two parties are equally invested in delivering legislation on infrastructure, health care, prescription drug prices, and veterans affairs. Tammy Baldwin held off a challenge from Republican Leah Vukmir, but her fellow Democrats Heidi Heitkamp of North Dakota and Claire McCaskill of Missouri were defeated by their Republican opponents.
Democrats had strong nights in both the Midwest/Rustbelt region and in the Southwest part of the United States, the regions of the country which will decide the 2020 presidential election.