When Democrats took control of the House after the last election, the question many had was whether they would focus on passing legislation or spend the next two years talking about Trump’s tax returns.  The answer has become pretty clear, with the Democrats holding, announcing, or threatening hearings or investigations on Trump/Russia collusion, Trump tax returns, Trump business dealings, Trump corruption, Trump abuse of power, Trump hush money payments, Trump obstruction of justice, Trump impeachment, Trump, Trump, and more Trump.

“The Constitution ... provided no express powers for Congress to investigate, issue subpoenas, or to punish for contempt,” according to a Congressional Research Service report.  But the practice was carried over from the British House of Commons whose members were considered the “grand inquisitors of the realm”.  (id., p.1)  Congress’ power to investigate is implied from its enumerated powers and the Necessary and Proper Clause, all found in Article 1, Section 8.

The first Congressional investigation of the executive branch appears to have been in 1791, when prior business dealings of the Superintendent of Finance Robert Morris were called into question. (id., p.2) 

The Supreme Court first placed limits on congressional investigations in 1821 [Anderson v. Dunn] (id. p.4).  The Court upheld Congress’ power to hold people in contempt, but said Congress must use the least onerous means to achieve its legislative objectives and no term of imprisonment Congress imposed could extend beyond a Congressional term.  In 1881, the Court placed more limits, saying Congress could not inquire into the personal affairs of individuals without actual “valid legislation” in mind.  (id. p.5)  This was later loosened to any legislative purpose, including oversight of alleged wrong-doing in the executive branch.  (id. p.5)  Oversight could potentially result in legislation, so a later Court viewed it as fair game for Congressional hearings and investigation.

The Supreme Court has also upheld Congress’ power to issue subpoenas as “an indispensable ingredient of lawmaking.”  (id. p.6)

Congress has expanded its powers to investigate by statute on a number of occasions, notably after 1946.  Congress beefed up oversight committee staff and upgraded the Government Accountability Office - GAO.  Congress now requires more than 2,000 reports from the executive branch every year. 

It’s a pretty safe bet that specific constitutional issues will come up as the House Democrats’ obsession with Donald Trump plays out.  Will witnesses ‘take the 5th’ like Lois Lerner did?  They’re certainly entitled to.  The Supreme Court ruled that “[t]he Bill of Rights is applicable to congressional investigations, as it is to all forms of governmental action” in 1957 [Watkins v. United States].  Will Trump administration officials claim executive privilege and refuse to turn over documents?  That didn’t work out so well for President Nixon [United States v. Nixon, 1974].  A unanimous Supreme Court rejected his claim of executive privilege and he resigned 16 days later.  I’ll keep an eye out for specific issues that come up as the Democrats move forward and report back to you when I can add to your understanding of the constitutional dimensions of what is happening.