WASHINGTON – After weeks of clashes, Congress and the White House seem to have finally figured out what they're fighting over: Everything.

And they're setting up a series of legal battles that could reshape the boundaries of presidential power and legislative oversight.

A request for President Donald Trump's tax returns? The Treasury secretary called it "unprecedented" with "serious consequences" for taxpayer privacy. Testimony from a White House staffer about security clearances? The administration blocked his appearance. Requiring documents and testimony from a former White House counsel? The administration is considering asserting executive privilege to prevent it.

Every administration has fought with Congress, but seldom like this. Lawmakers are seeking information that would shed light on Trump's personal affairs, and the White House has responded with personal attacks. Instead of battling over one or two issues, lawmakers have made clear that they intend to dig widely into the president's conduct. The White House has signaled it will fight them on every front.

"We're fighting all the subpoenas. These aren't like impartial people. The Democrats are trying to win 2020," Trump said Wednesday. "The only way they can luck out is by constantly going after me on nonsense."

The disputes appear headed to federal courts, a prospect that could embroil all three branches of government in a test of presidential power. Trump himself has already launched one such fight, suing to block his longtime accountant from providing financial records to congressional investigators.

“This is a massive, unprecedented, and growing pattern of obstruction," Rep. Elijah Cummings, the Maryland Democrat who heads the Oversight and Reform Committee, said Wednesday.

The atmosphere is so combative that routine requests have become skirmishes. Commerce Secretary Wilbur Ross refused to testify this month at the House Appropriations Committee and in late March at the Senate Appropriations Committee, where he was expected to face questions about adding a citizenship question to the 2020 census.

Mark Harkins, a senior fellow in the government affairs institute at Georgetown University and former House Democratic staffer, called Ross' refusal "astounding."

"What is unusual is the number of different fronts," Harkins said. "The personal nature of the current bout of congressional oversight, such as wanting tax returns and financial records prior to serving in office, is what distinguishes the current bout of friction."

Trump emerged from the shadow of Justice Department special counsel Robert Mueller's inquiry only to find a cascade of other investigations.

Mueller found that Trump hadn't conspired with Russia to influence the 2016 election. But Mueller's report revealed in startling detail the Russian government's "sweeping and systematic" efforts to help Trump win, how his campaign welcomed the help and how Trump sought to impede the investigation.

Democrats, who regained control of the House in January, are using their newfound political power to explore everything from the Trump administration's policies to the president's conduct before he took office. They have issued formal demands for his tax returns and other financial records.

That is what provoked Trump in February to call the investigations "unlimited presidential harassment," tweeting that lawmakers would be "looking at every aspect of my life, both financial and personal, even though there is no reason to be doing so."

Congress looks into Trump finances

A half-dozen House committees are examining Trump's finances for evidence of corruption and foreigners who might influence him. Those inquiries accelerated after Trump's former personal lawyer, Michael Cohen, accused the president in sworn testimony this year of inflating his assets to obtain bank loans, participating in a financial conspiracy and encouraging him to lie to Congress.

Based on Cohen's testimony, the House Oversight and Reform Committee issued a subpoena for Trump's business records turned over to his accountant before he was elected in 2016. But Trump and his businesses filed a federal lawsuit Monday against the committee, to block another subpoena to Trump’s longtime accounting firm Mazars USA that sought financial documents.

Congress has sued the past six presidents to get information when their requests went unanswered, Harkins said, but it is unusual for the president to file a lawsuit himself to block their demands.

The House Ways and Means Committee requested Trump’s tax forms from the Internal Revenue Service by Tuesday, but the panel hasn’t received them. In a break with more than 40 years of tradition by presidents and nominees, Trump has refused to release his returns.

Treasury Secretary Steven Mnuchin replied Tuesday that it would make a final decision by May 6, but he accused the committee of seeking the returns not for the stated purpose of drafting legislation but "to publicly release the president's tax returns."

No cooperation despite subpoenas

One of the latest fights erupted Tuesday when Carl Kline, the White House personnel security director, refused to testify at the House Oversight and Reform Committee about security clearances – despite a subpoena. Cummings said he would consult with the House counsel and lawmakers to set up a potential vote for contempt.

Security clearances became controversial because of reports that Trump personally ordered that a security clearance be provided to Jared Kushner, his son-in-law and a senior adviser, despite concerns about his meetings with foreign nationals. Kline is accused of retaliating against a whistle-blower, who told lawmakers how about 25 clearances were granted despite problems with people's background checks.

“To date, the White House has refused to produce a single piece of paper or a single witness in any of the Committee’s investigations this entire year,” Cummings said Tuesday. “The White House now seeks to stonewall this otherwise routine congressional process.”

The administration blocked another request for information on Wednesday, saying it would not allow a top official to testify about the administration's plans to add a citizenship question to the census. Lawmakers had planned to depose John Gore on Thursday, but Barr said Gore wouldn't appear unless another lawyer could accompany him to advise him about confidentiality interests of the executive branch.

Similarly, lawmakers are pressing for full Mueller report, so far without success. The House Judiciary Committee subpoenaed the complete Mueller report – and former White House counsel Don McGahn, who was described in the report as resisting Trump's efforts to stymie the inquiry. Several committees continue to explore the president's attempts to thwart the federal investigation into Russian influence in the election, despite Mueller pressing no charges.

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“President Trump and this administration are engaged in unprecedented stonewalling and once again using the legal system to conceal every area of his life as well as his wrongdoing and improprieties from the American people," said Ashley Etienne, a spokeswoman for House Speaker Nancy Pelosi, D-Calif. "This level of secrecy should alarm all Americans."

One of Trump's personal lawyers, Rudy Giuliani, who represented Trump during the Mueller investigation, said he supports the White House's aggressive approach. Giuliani called the Democratic congressional elections "patently political."

"I would fight all those subpoenas," Giuliani said. "I haven't seen one yet that has a legislative purpose."

Broad sweep of inquiries unusual

Conflicts between Congress and the White House are expected between equal branches of government, according to academic experts. But the wide variety of conflicts and the personal nature of some of the requests are different with Trump.

Former President Barack Obama's Attorney General Eric Holder fought with the Oversight Committee over a gun-running case and former President George W. Bush's Justice Department was investigated over the firing of U.S. attorneys. Former President Bill Clinton was impeached after an investigation gathered evidence about his sexual relationship with a White House intern (the Senate did not remove him from office).

But Sarah Binder, a senior fellow at the Brookings Institution and professor of political science at George Washington University, said the difference today is the wide variety of the conflicts, such as when the House Judiciary Committee requested documents from 81 people and organizations. The disputes have also resulted in subpoenas, which themselves represent the failure of negotiations to provide information voluntarily, she said.

“There’s certainly precedent for these sorts of fireworks when the administration doesn’t want to comply, particularly during a period of divided government, with an investigation run by the other party," Binder said. “I would say just generally that the Trump administration’s relationships with the Hill have been so fraught that we shouldn’t be surprised that they are coming to a head in this way, where past administrations might have had an incentive not to blow everything up at once because they wanted to get something else done."

As Democrats press their subpoenas and Trump resists, the fights seem likely to land in federal court, where fights over information have been known to drag on for years with uncertain results.

"In the past, the Supreme Court has given wide latitude to Congress in what it can obtain in its role in overseeing the executive branch," Harkins said.

Trump tweeted again Wednesday that he has done nothing wrong and that he had allowed everyone to testify to Mueller's investigators, including McGahn. But he said he would not permit his former White House lawyer to go before Congress. "I say it's enough," he said.

Contributing: John Fritze, David Jackson and Eliza Collins

More about congressional requests from President Donald Trump:

President Trump still facing swirl of investigations even after Robert Mueller's probe has ended

Deadline for Trump's tax returns to Capitol Hill: White House said returns won't be released

President Trump and his businesses ask a court to block Congress from obtaining accounting records

Reports: Trump ordered son-in-law Jared Kushner be granted top-secret security clearance

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