(CNN) Key House Democrats who have avoided questions about impeachment in the past say that President Donald Trump could be exposing himself to another potential avenue for impeachment by obstructing congressional investigations .

The White House's all-out refusal to cooperate with the House Democratic investigations have some Democrats questioning whether Trump's blatant disregard for congressional oversight is yet another kind of obstruction of justice that could rise to the level of "high crimes and misdemeanors."

Democrats say they're not ready to launch impeachment proceedings yet. But faced with the prospect of months -- if not years -- of court battles to obtain information from their subpoenas , they are publicly expressing more of an openness to the idea than they have at any point since Mueller's investigation ended last month

In recent days, Trump administration officials have defied subpoenas for congressional interviews, the Department of Treasury missed another deadline to turn over the President's tax returns, and Attorney General William Barr's testimony before the House Judiciary Thursday is now in question because the Justice Department is objecting to the format of the congressional hearing on the basis Judiciary Committee Chairman Jerry Nadler wants to include questioning from both Republican and Democratic staff lawyers.

"The President and the executive branch have to produce witnesses, and they have to produce documents when we ask for them," said Rep. Jamie Raskin, a Democrat on the House Oversight Committee. "I think the President has escalated the conflict with Congress. The obstructionism that we read about in the Mueller report has come galloping off the pages and right onto our front doorstep."

The fight for information between Congress and the White House has grown so contentious in recent days that Rep. Gerry Connolly , another Democrat on House Oversight, has said that the President is pushing Democrats into the impeachment camp who otherwise wouldn't have been there.

"It is my sense a lot of people share that view," Connolly said Tuesday.

For Democrats who had been reluctant to spend the next 18 months in the throes of a politically contentious impeachment battle when the next election is just around th, corner, the administration's defiance to comply with requests for information is making the case for impeachment worse, not better for the President.

"If there's anything that's going to get me there, it's the fact that the President contravenes the constitutional requirement of oversight, compliance with oversight," House Intelligence Committee Chairman Adam Schiff said at a Washington Post Live event Tuesday. "If he is willing to flout the law in that way also, he is going to make an even more powerful case for an impeachment proceeding."

In the last several days, the President himself has been transparent about his administration's defiance.

"We're fighting all the subpoenas," Trump said last week . "These aren't like impartial people. The Democrats are trying to win 2020. They're not going to win with the people I see and they're not going to win against me."

Last week alone, two individuals -- Carl Kline , who previously oversaw the security clearance process at the White House, and John Gore, the principal deputy assistant attorney general -- refused to comply with congressional subpoenas from the House Oversight Committee.

Kline agreed to appear this week after a leading Republican on the Oversight Committee stepped in , but House Oversight Committee Chairman Elijah Cummings has said he still won't hesitate to hold Kline in contempt of Congress if the committee's questions aren't answered. The White House also threatened to fight a subpoena for former White House counsel Don McGahn. And Trump and his family have sued major financial institutions including Deutsche Bank, Capital One and accounting firm Mazars USA to block them from handing over financial information about the President and his related businesses.

"Whether it is refusing to sit down in an interview with Mueller or whether it is constantly obstructing justice by trying to stop testimonies and stop people from cooperating, whether it is filing a lawsuit, he obviously has something to hide," said House Financial Services Committee Chairwoman Maxine Waters.

"If the President truly feels he's been exonerated (and) he did nothing wrong, he should do nothing to try and stop someone from coming to talk to us," said Rep. Mark Pocan, a Democrat from Wisconsin. "If he's going to try to obstruct witnesses coming to talk to Congress, he might be pushing us into something else, but right now just as back home people understand the next steps are bringing some witnesses. If Donald Trump did nothing wrong, he shouldn't be doing anything to block people coming to talk to Congress."

Rank-and-file members are still united against an urgent action to impeach Trump, but members say that the administration's refusal to comply with congressional oversight is beginning to be a major problem.

"I think it's the totality of the whole picture, so we'll see what happens as we have very strong committees looking at these issues. What absolutely nobody can disagree with is that our founding fathers gave Congress the responsibility for oversight," said Rep. Debbie Dingell, a Democrat from Michigan. "We're now in that process and we'll see how the White House responds and ways we move forward. We have very good competent people managing this. "

Defiance from the Trump administration not only keeps the party from getting answers, it could also distract from the Democrats' ability to move ahead with policy priorities and it could impact the base, which already is applying pressure to force Democrats to push ahead with impeachment before the next election.

"If every single request from Congress to the executive requires a subpoena and a fight in court over the legitimacy of that, it's going to take an awful lot of time and energy that could be devoted to other more productive efforts," said Rep. Stephen Lynch, a Massachusetts Democrat, pointing to a potential massive infrastructure deal that has so far remained elusive during Trump's presidency.

Asked if the administration's continued stonewalling of Congress could advance to impeachment, Lynch responded "it would put more weight behind that argument."

Republicans have accused Democrats of trying to make it look like they're moving forward with impeachment to satisfy their base without actually taking the steps to do so.

Georgia Rep. Doug Collins, the top Republicans on the House Judiciary Committee, pointed to the demand from Nadler for staff to interview Attorney General William Barr at Thursday's hearing on the Mueller report, a format that has been used by the committee in prior impeachment hearings for former Presidents Richard Nixon and Bill Clinton.

"The Democrats are looking for the optics of the impeachment hearings," Collins told CNN. "They want this hearing to look like an impeachment hearing, but they do not have the votes or do not have the fortitude to bring an impeachment resolution."