House Democrats have 'penetrating and far-reaching' power to investigate Trump -- and to make new laws to restrain him
Rep. Nancy Pelosi, D-Calif. facing off with President Trump at the White House on Dec. 11. (Photo: Brendan Smialowski /AFP)

House Democrats have the legal authority to see President Donald Trump's tax returns and the full report from special counsel Robert Mueller -- if only they would exercise their power.

Congress has strong investigative powers to root out corruption and mismanagement, even if those actions are being investigated elsewhere, and the Supreme Court has established clear guidelines for exposing misconduct in both the federal government and the private sector, according to former congressman Brad Miller in an essay for The Daily Beast.

“The power of the Congress to conduct investigations is inherent in the legislative process," the court ruled in Barenblatt v. United States. “It encompasses inquiries concerning the administration of existing laws as well as proposed or possibly needed statutes.”

“The scope of the power of inquiry, in short," the court ruled in Watkins v. United States, "is as penetrating and far-reaching as the potential power to enact and appropriate under the Constitution.”

Congress conducted hearings on organized crime and union corruption -- which were dramatized in the "Godfather" movies -- that resulted in significant legislation, including 1970's Racketeering Influence and Corrupt Organizations Act (RICO) that made criminal prosecution of mob bosses much easier.

House Democrats could push legislation requiring presidential candidates to release their tax returns, which Trump has refused to do and now is fighting a legal battle against doing, and Congress could make specific adjustments to laws regarding corruption and the emoluments clauses.

Lawmakers could also close tax loopholes or increase the budget for tax enforcement, as well as revisiting the independent counsel law, argued Miller, who represented North Carolina from 2003 to 2013.

Trump can rage against the various investigations into his administration and past business, but Miller argued the Supreme Court has been clear on congressional oversight authority.

“When a committee of Congress is engaged in a legitimate legislative inquiry and the questions propounded are relevant and material to the inquiry, the courts will not question the motives of the questioner,” the Supreme Court has ruled.