The prospects of the House managers winning conviction and removal of President Trump in the Senate impeachment trial were always dim. As long as Republican voters stick with the president, Republican politicians will follow, even if they think the president has engaged in serious misconduct. That means Republican senators will be looking for an adequate rationale for voting to acquit Trump. The president’s defense team has provided some possible justifications for an acquittal, but they are bad ones.

If Republican senators do vote to acquit the president, it is imperative that they not wind up endorsing a dangerous view of presidential power and crippling their own institution in the process. As in the impeachment trials of Presidents Andrew Johnson and Bill Clinton, each senator will have an opportunity to go on record with an explanation of his or her vote. If those statements endorse the most extreme versions of the defense team’s arguments, they will set a very dangerous precedent for the future. Senators will need to be clear that although they are not voting to remove Trump for his conduct, they are also not giving future presidents carte blanche to abuse the powers of their office.

The easiest and least consequential grounds for voting to acquit would emphasize the facts and evidence of this individual case. If the House managers had not met whatever burden of proof each senator thinks is appropriate to a presidential impeachment trial, then senators could vote to acquit without endorsing any particular view about the constitutional scope of the impeachment power and the contours of impeachable offenses. Unfortunately, it is very hard to make that argument if the Senate refuses to hear any witnesses or subpoena any documents at the trial. It is hard to assert the House managers have not provided enough evidence to support their case when the Senate itself is barring the managers from introducing all the available evidence. By cutting the trial short, senators will be boxing themselves in on what credible explanations they can offer to justify their final vote. They will find themselves having to argue the law rather than argue the facts.

Professor Alan Dershowitz was given the task of making the argument that even if the charges against the president were factually true, they still did not justify removing the president under the terms of the Constitution. Dershowitz chose to fulfill that task Wednesday by arguing for an extraordinarily narrow understanding of the scope of the constitutional standard of high crimes and misdemeanors. He claimed the impeachable offenses should be restricted to “specific violation of preexisting law” and “criminal-like conduct.” Moreover, he asserted mere “abuse of power” can never be the basis of a constitutionally valid impeachment because the framers would have rejected such a “vague and open-ended” standard for fear it would convert the American constitutional system into a British-style parliamentary system. He said Thursday he hadn’t meant all this, but it was the clear implication of the argument he presented in the Senate the night before.

This understanding of the constitutional scope of impeachable offenses is well outside the scholarly mainstream and sharply at odds with our constitutional text, structure, purpose, original meaning and historical practice. Dershowitz went as far as to suggest that as long as a president might think his actions are in the public interest, any noncriminal act that might help him or his political party win reelection would be beyond the reach of the impeachment power (though he admits a criminal act would be impeachable).

If Dershowitz is right, even the articles of impeachment that were drafted against President Richard Nixon would have been constitutionally defective. Nixon was not the first president to try to use the power at his command to investigate and spy on his political enemies, but the Watergate scandal was part of the process by which Americans insisted presidents should never take such actions again. The ignominious end of the Nixon administration stood as a warning to presidents not to attempt such abuses of power in the future.

If Republicans in the Senate were not only to acquit Trump but also to endorse the constitutional argument that Trump’s lawyers made on his behalf, they would be taking a large step toward undoing the lessons of Watergate. They would be inviting future presidents to think that there is only one possible check on the abuse of power, and that is the ballot box. They would be crippling the ability of future Congresses to hold presidents accountable for abuse of power and to deter presidents from running the risk of facing an impeachment inquiry for their misconduct while in office.

So when senators do vote to acquit, they must take the opportunity to make plain that presidential abuse of office is still intolerable. They must make clear that abuse of power is still, as it always has been, a high crime and misdemeanor and an impeachable offense. They must emphasize the failure of the Senate to convict and remove this particular president at this particular time does not mean that all noncriminal presidential misconduct is outside the scope of the constitutional impeachment power.

Senators might reasonably conclude, for instance, that even impeachable offenses need not result in immediate removal. When the House is confronted with an officer who has committed impeachable offenses, it must still decide whether an impeachment is the best remedy for that misconduct and necessary to prevent future misconduct. Likewise, when the Senate is asked by the House to convict and remove an officer, senators must consider whether removal is necessary to preserve the integrity of the American constitutional system. Both the decision to impeach and the decision to convict are discretionary and require an exercise of political judgment.

In some cases, impeachment and removal might be the only reasonable options. Congress must step in if a life-tenured federal judge refuses to resign the office after being exposed as corrupt. No other remedy is available. There are also circumstances in which the Senate should not hesitate to convict and remove a sitting president who is actively endangering the nation through his or her misconduct.

But there are also circumstances in which the Senate might think the immediate removal of an officer is not necessary. Some number of senators might conclude, after examining the accusations against a president, that the nation and the constitutional system can tolerate even a disgraced chief executive serving out their term of office. Other steps might be taken to limit the damage that a misbehaving president can do. The voters might be given the opportunity to decide just how serious the president’s misconduct is and how they prefer to balance the risks and benefits of allowing that individual to continue to serve in office.

Senators can say the charges leveled against Trump are not sufficient to justify his immediate removal without taking the additional step of saying charges of this sort do not fall within the constitutional scope of the impeachment power. Senators should leave the door open to future impeachments for abuse of power. If senators embrace the constitutional arguments put forward by Trump’s defense, they will embolden future presidents to engage in their own abuses of office and weaken the ability of future Congresses to check those abuses. For the sake of the Congress and of the Constitution, they should take care that in voting to acquit this president they do not do lasting damage to institutions that they have a duty to preserve and protect.

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