Lifelong liberal, Democrat, constitutional scholar and Harvard professor Alan Dershowitz against impeachment.

https://www.gatestoneinstitute.org/15120/weaponizing-impeachment

To be impeached, a president must commit a crime (misdemeanor is a species of crime) and the commission of that crime must also constitute an abuse of office. An abuse of office without an underlying crime is a political sin, but not an impeachable offense.

This very issue was debated at the Constitutional Convention, where one delegate proposed "maladministration" as the criteria for impeachment and removal of a president. James Madison, the Father of our Constitution, strongly objected on the ground that so vague and open-ended a criterion would have the president serve at the will of Congress and turn us from a Republic with a strong president into a parliamentary democracy in which the chief executive can be removed by a simple vote of no confidence. Instead, the Convention adopted strict prerequisites for impeachment: treason, bribery or other high crimes and misdemeanors. The House is no more empowered to substitute its own criteria for those enumerated in the Constitution than the Senate would be to change the 2/3 vote requirement for removal to a simple majority or a 3/5 super majority. Congress is not above the law. It is bound by what the Framers accepted and cannot now apply the criterion the framers explicitly rejected.

Those who characterize the impeachment and removal process as completely political are wrong as a matter of constitutional law, even if they are right in describing the reality of how it is being currently misused.

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A partisan House vote to impeach President Trump, followed by a partisan Senate vote to acquit him, would not only hurt the Democratic Party — as the votes in the Clinton case hurt the Republican Party — it would damage our constitution and further polarize our already divided nation.

Most important, misusing the impeachment power in a partisan manner would pose, in the words of Hamilton, "the greatest danger" to our Constitution.