If the House of Representatives were to impeach President Trump on the two grounds now before it, the senate would be presented with a constitutional dilemma.
These two grounds - abuse of power and obstruction of Congress - are not among the criteria specified for impeachment. Neither one is a high crime and misdemeanor. Neither is mentioned in the constitution.
Both are the sort of vague, open-ended criteria rejected by the framers.
They were rejected precisely to avoid the situation in which our nation currently finds itself.
Abuse of power can be charged against virtually every controversial president by the opposing party.
And obstruction of Congress - whatever else it may mean - cannot extend to a president invoking privileges and then leave it to the courts to referee conflicts between the legislative and executive branches.
Hamilton feared that vague criteria would allow a majority of the House to impeach a president from the opposing party just because they had more votes than the president's party. He called that "the greatest danger." Madison worried that open-ended criteria, such as "maladministration" would give Congress too much discretion and power, and turn our republic into a parliamentary democracy in which the chief executive serves at the will of the legislature. To prevent these dangers, the framers settled on criteria with well-established meanings: treason, bribery and other high crimes and misdemeanors.
The House Democrats are simply ignoring these words and this history, because they have the votes to do so. They are following the absurd notion put forth by congresswoman Maxine Waters that when it comes to impeachment "there is no law," and the criteria are anything a majority of the House wants it be, regardless of what the constitution mandates. This lawless view confuses what a majority of congress can get away with (absent judicial review) with what the constitution requires. It places Congress above the supreme law of the land, namely the constitution.
Were Congress to vote to impeach President Trump on the two proposed grounds, its action would be unconstitutional. According to Hamilton in Federalist 78, any act of Congress that does not comport with the Constitution is "void." This view was confirmed by the Supreme Court in Marbury v. Madison and is now the law of the land.
So, what options would the Senate have if the House voted to impeach on two unconstitutional grounds? Would it be required to conduct a trial based on "void" articles of impeachment? Could it simply refuse to consider unconstitutional articles? Could the president's lawyer make a motion to the Chief Justice — who presides over the trial of an impeached president — to dismiss the articles of impeachment on constitutional grounds?
This is uncharted territory with little guidance from the Constitution or history. There are imperfect analogies that may be informative. If this were an ordinary criminal case, and a grand jury had indicted a defendant for a non-crime (say, having gay sex) or an unconstitutional crime, the trial judge would be obliged to dismiss the indictment and not subject the defendant to an unconstitutional trial. Impeachment, however, is not an ordinary criminal proceeding. So, the analogy is not directly on point. But impeachment by the House is similar in many ways to indictment by a grand jury, and a removal trial by the Senate is similar to a criminal trial, including being presided over by a judge.
It is entirely possible that the president's lawyers may file a motion seeking dismissal of the impeachment as unconstitutional. It is impossible to predict whether such a motion would be entertained and if so, how it would be decided.
Another option would be for the president's lawyer to seek judicial review of the House's unconstitutional action. Despite the fact that the Constitution says that the House shall be the "sole" judge of impeachment, two former justices have opined that there might be a judicial role in extreme cases.
The most likely option for the president — and the one hinted at by White House sources — is for the Senate to conduct a scaled down trial focusing on the constitutional defects in the articles of impeachment. No fact witnesses would be called: that would turn the proceeding into a he said/she said conflict with no clear resolution. Only legal arguments — neater and quicker — would be presented before a vote was taken.
Whichever option is pursued, the ultimate outcome seems clear: the Senate will vote to acquit President Trump. Regardless of the outcome, the damage will have been done by the House majority that will have abused its power by weaponizing the House's authority over impeachment for partisan purposes — exactly as Hamilton feared.