House Democrats are beginning to ramp up oversight of the Trump administration, the president's policies and his potential conflicts-of-interest, efforts that are underway after Congress was delayed by a 35-day government shutdown and sidetracked by border security negotiations.

Many newly formed House committees are set to hold their first oversight hearings this week after President Trump's State of the Union, as others prepare to hear from top administration officials, after weeks of standoffs over information and testimony that has led some Democrats to weigh the possibility of issuing their first subpoenas.

"Obviously the pace of oversight has been affected very directly by the shutdown and everyone having to shift priorities," Rep. Raul Grijalva, D-Ariz., chairman of the House Natural Resources Committee, told ABC News. "We're moving in that coordinating direction. That got suspended, so we're back on the train."

The House Ways and Means Committee, whose chairman, Rep. Richard Neal, D-Mass., is preparing to request the president's tax returns under an obscure 1920s law, will hold a subcommittee hearing this week on a piece of a new proposal that would require presidential nominees release their tax returns.

And the House Energy and Commerce Committee's oversight subcommittee on Thursday will hold a hearing on the Trump administration's family separation policy.

The inauspicious start to the new relationship between Democrats controlling the House and the Trump administration has set the stage for a particularly fraught two years of political battles in Washington under divided government.

"There is a political strategy of obstruction and disruption right now," Rep. Joaquin Castro, D-Texas, a member of the House Intelligence and Foreign Affairs Committees, told ABC News.

Testimony tug-of-war

On Friday, Acting Attorney General Matthew Whitaker is expected to testify before the House Judiciary Committee, after grappling with Democrats over an appearance during the shutdown, and Chairman Jerry Nadler's public threat to compel his appearance.

Other Cabinet secretaries have spurned Democrats' early demands to appear before committees of jurisdiction to testify on the impacts of the government shutdown and the state of their agencies.

Some, such as Treasury Secretary Steven Mnuchin, have engaged with Congress in fits and starts: Mnuchin appeared to brief House lawmakers behind closed doors on the department's decision to ease sanctions on companies linked to Russia billionaire Oleg Deripaska, but angered lawmakers with Treasury's decision to lift the sanctions over opposition from a majority of the House and Senate.

Mnuchin, whose personal financial dealings are now under scrutiny from Democrats, now faces demands from the House Intelligence and Financial Services Committee to provide new documents and information about the move this week.

"Cabinet members don't have a choice," Rep. Gerry Connolly, D-Va., a senior member of the House Oversight Committee, told ABC News. "They are legislatively confirmed, and they are accountable to the legislative branch."

Others, including Health and Human Services Secretary Alex Azar and Homeland Security Secretary Kirstjen Nielsen, have sparred with top Democrats over testifying in the early weeks of the session.

Rep. Bennie Thompson, D-Miss., the chairman of the House Homeland Security Committee, told reporters he would consider issuing a subpoena to compel Nielsen to testify, even as he acknowledged the limitations of an aggressive approach.

"It's a meat-ax approach that you're taking to legislating," he told ABC News. "But if there's a reluctance to talk to chairpersons and other things, I think those individuals don't leave you much choice."

On Monday, Thompson and Rep. Mike Rogers, R-Ala., the top Republican on the committee, announced an agreement for Nielsen to appear on Capitol Hill in March.

While the White House counsel's office hasn't issued any formal guidance to government agencies, the office has been working closely with top lawyers at various agencies to assist them in dealing with the influx on congressional requests, whether it be testimony or requests for documents, according to sources familiar with the matter.

The office has also bulked up, with White House Counsel Pat Cipollone adding at least 17 attorneys to the counsel's office since taking over the White House legal operation.

White House lawyer Emmet Flood, a veteran Washington attorney who previously represented President Bill Clinton and Vice President Dick Cheney, has also been briefing staffers at government agencies, sessions that sources have described as more "process-oriented not political posturing" when it comes to congressional requests. Sources familiar with the nature of the briefings say there is not currently a coordinated effort from the White House advising Cabinet secretaries not to testify.

Flood has also briefed senior White House staff on congressional oversight ahead of the investigations. White House cooperation with congressional requests will be evaluated on a case by case basis, according to sources involved in the process. The White House has not ruled out challenging some requests on executive privilege grounds, as other presidents have done in response to requests from Capitol Hill.

Confrontations between administration officials are nothing new: In 2008, the Democrat-led House held Bush chief of staff Joshua Bolten and former White House Counsel Harriet Miers in contempt of Congress after they refused to comply with congressional subpoenas. In 2012, Republicans in the House held Attorney General Eric Holder in contempt of Congress over refusing to turn over documents from the Fast and Furious operation to Hill investigators.

"Unfortunately it's become more common, the 'If you want me, come get me!'" Tom Davis, a former Virginia congressman and chairman of the House Oversight Committee, told ABC News of administration officials resisting Capitol Hill overtures.

But Democrats, he said, are grappling with a "pent up" demand for oversight following the Republican House in the first two years of the Trump administration.

Balancing act

With congressional Republicans and the White House eager to accuse the new majority of prizing targeting of the president and scoring political points over legislation, Democrats have proceeded cautiously with their committee work, picking targets and pairing hearings about administration actions with others on policy initiatives.

The House Oversight Committee, which is working to schedule a public hearing with former Trump lawyer Michael Cohen after he canceled a public appearance for Thursday, held its first open hearing on prescription drug prices, featuring expert witnesses and the mother of two Insulin-dependent daughters rather than drug company executives.

The House Intelligence Committee, which will meet for the first time on Wednesday and is expected to vote to transmit transcripts of its Russia investigation interviews to special counsel Robert Mueller, has scheduled a private meeting with Cohen for Friday, and is planning to hold its first public hearing on the rise of authoritarianism, according to Chairman Adam Schiff, D-Calif.

The House Judiciary Committee, ahead of its highly-anticipated hearing with Whitaker, held a hearing on H.R. 1, Democrats' good-governance package, and has another scheduled on gun violence.

"They have to orchestrate this thing and be careful when they come out of the box to make sure they're not overshooting," Davis said. "You're laying a predicate for the next two years with how you get into this."