After sweeping both chambers of the US Congress, Democrats will turn their new investigative powers on the Trump family's business deals as they make what they call corruption a central part of a 2028 campaign for the White House.

Democrats seized control of both the Senate and House of Representatives in Tuesday's midterm elections, in which tens of millions of voters delivered a rebuke to President Donald Trump. They wasted no time putting Republicans on notice.

"LAWYER UP," US Representative Robert Garcia, who is set to become chairman of the House Oversight Committee, posted on X late on Tuesday.

"Subpoenas," Senator Ron Wyden, who is expected to lead the Senate Finance Committee, wrote an hour later.

"Clear your schedule," US Representative Delia Ramirez said in a post addressed to several Trump administration officials.

Democratic committee leaders began outlining an oversight agenda on Wednesday that targets both the Trump administration and major corporations. Wyden said he plans to scrutinize agreements between the Trump administration and pharmaceutical companies on drug pricing.

The Trump administration has denied any wrongdoing and on Wednesday it pushed back against the looming probes.

"If Democrats choose to pursue sham investigations and radical left policies, they are choosing to work against the American people," said White House spokesperson Lauren Bis.

Another White House official, speaking on the condition of anonymity, said of the comments by Democrats: "They should be reminded that we still control the federal government and all of its powers," the official said.

Tech CEO and Republican mega-donor Elon Musk, Trump's sons and a swath of other Republican donors and contractors are likely to be swept up in investigations that could dominate the second half of Trump's term, according to Reuters interviews with around a dozen lawyers, members of Congress, congressional aides and political consultants. A representative for Musk did not respond to a request for comment.

A representative for Donald Trump Jr., one of the president's sons, declined to comment, while one for Eric Trump, another son, did not respond to a request for comment.

Democrats have opted for investigations rather than trying to impeach Trump immediately, Reuters previously reported.

"We expect a huge volume of aggressive and expansive investigations that will target both the administration and the private sector," said lawyer Rachel Cotton, a congressional oversight specialist at the Arnold & Porter law firm.

Analysts say that Democrats will have to walk a fine line between seeking to expose what they call unprecedented corruption under Trump and addressing voters' concerns about higher prices for consumer goods and gasoline.

Whether Democrats succeed will have major implications for a so far wide-open race to succeed Trump in the 2028 presidential election.

"The Democrats will be less concerned with Trump and more about tying the corruption to the whole administration and ultimately to the entire" Republican party, said Sarah Longwell, a former Republican strategist and longtime Trump critic, adding that part of the aim will be to erase a political path for Trump administration officials.

Longwell said that Democrats could also benefit politically from probing how Republicans handled information around the late sex offender Jeffrey Epstein. "Even if it's more political theater than anything else, any time we're talking about Epstein, Trump's popularity is suffering," she said. Yet Democrats risk overplaying their hand, said Republican consultant Ron Bonjean.

"Voters are more concerned about affordability," Bonjean said. "If the vengeance that Democrats are seeking overwhelms their legislative agenda then they're likely to have a very short legislative majority." Some 48% of registered voters in a Reuters/Ipsos poll conducted nationwide from Thursday last week through Monday said cost of living was the top issue determining their vote.

But voters have also expressed concern about Trump's personal enrichment amid his family's flurry of crypto and real estate deals. In an August Reuters/Ipsos poll, some 69% of Americans said they thought his private business interests were influencing his presidential decisions.

For any investigations to succeed, Democrats will have to avoid getting bogged down in litigation with a combative White House and keep what could be a raucous coalition in line, lawyers and congressional aides said.

"There will be a lot of pressure on Democrats to issue subpoenas early. But the juice has to be worth the squeeze for whatever they decide to litigate," said lawyer Kimberly Hamm with Morrison Foerster.

The House, which will likely move faster than the Senate, should be narrow in its asks and strategically try to limit the potential objections from the White House, said Hamm.

Corporations are prime targets for investigations because, unlike the White House, they cannot claim their activities are protected by executive privilege, although the White House could step in and claim they are, lawyers said.

Winning the Senate gives Democrats a "broader field" on which to play, said lawyer Mike Fragoso with Torridon Law.

"But there's only so much time in the day and time in a Congress," said Fragoso. "The question is how willing and able they will be to pick their targets and focus on them."