A growing investigative dispute between Democrats in Congress and President Donald Trump deepened on several fronts Tuesday, with the Trump Administration questioning the basic ability of Congress to conduct oversight of the Executive Branch, as one former security aide defied a subpoena for Congressional testimony from a House committee, and the President made clear he's had enough of Democrats seeking more information about the Russia investigation.
"Article I grants Congress no express power to investigate," said Secretary Steven Mnuchin in a letter to the House Ways and Means Committee, in which for a second time this month, the Trump Administration refused to turn over the President's tax returns, requested by Democrats under a specific section of the Internal Revenue Code.
Meanwhile, a former security clearance official at the White House, Carl Kline, refused to show up for questions from the House Oversight Committee on Tuesday morning, as Democrats said the White House had ordered Kline - now working at the Pentagon - not to cooperate with a probe of why certain officials were given security clearances, after initially being rejected.
Kline's refusal to testify drew a sharp rebuke from Rep. Elijah Cummings (D-MD), who said his panel was getting nowhere with the White House on a number of investigations, as the Trump Administration game plan seemed to evolving into one in which all subpoenas and requests for information are challenged or parried.
"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, threatening to hold Kline in contempt.
As if those battles weren't enough, President Trump himself made clear in an interview with the Washington Post on Tuesday that he doesn't want to see his aides testifying on Capitol Hill in contentious hearings, especially about he Russia investigation.
That came amid questions over how the White House might try to block testimony by former White House Counsel Donald McGahn, who has been served with a subpoena to testify before the House Judiciary Committee about his comments in the Mueller Report.
"There is a reason Trump was okay letting McGahn speak to Mueller but is doing everything to block him from testifying in front of Congress," said Rep. Ro Khanna (D-CA) of the President. "He understands the power of television."
Democrats made clear they had no intentions of backing away from additional hearings about the investigation into Russian interference in the 2016 elections.
"The Mueller report includes the results of the criminal probe, but not the findings of the counterintelligence investigation," said Rep. Adam Schiff (D-CA), who chairs the House Intelligence Committee.
Staying away from television cameras on Tuesday, the President took to Twitter to jab at Democrats over their push to hold more hearings to explore questions in the 448 page Mueller Report.
"You mean the Stock Market hit an all-time record high today and they’re actually talking impeachment!?" the President tweeted, adding his summary: "NO COLLUSION."