More than once since the Democrats captured the House of Representatives in the midterm elections of 2018, President Donald Trump has taken to Twitter to express his irritation at “presidential harassment!” Undoubtedly, he is not the first occupant of the Oval Office to feel that way, but his response has been different. The Trump administration has tended to adopt a posture of maximal presidential obstruction of congressional investigations into the conduct of the executive branch and the individuals surrounding it. That defiance has culminated—for the moment—in White House Counsel Pat Cipollone’s letter to Speaker of the House Nancy Pelosi declaring that the administration will not cooperate in any way with an impeachment inquiry that it regards as “illegitimate” and “constitutionally invalid.”
That level of defiance is not healthy, and it might not end with the Trump administration. Congress and the White House have a tense relationship, and future administrations might well choose to build on rather than repudiate the Trump example of how to respond to a hostile Congress. If Trumpian defiance works, then it might well be repeated.
The basic purpose of congressional oversight can get lost in the fog of partisan combat. The U.S. Constitution does not vest an explicit power of oversight or investigation in Congress. The Constitution vests “all legislative Powers herein granted” to Congress, but investigative powers are not mentioned in the text, and investigative powers are not clearly legislative in nature. Nonetheless, judges and politicians have long understood legislatures to have the authority to do some investigative work. The English Parliament and the colonial state legislatures had exercised such powers, and the U.S. Congress started to exercise such powers soon after the ratification of the Constitution.