For all of you out there wondering what "High Crimes & Misdemeanors" means and whether or not there has to be an 'underlying crime' let me help you out here.
Last week I moderated a CLE on Impeachment and you are welcome to the fruits of my labors on that topic.
You have to use that term, and it is a legal 'term of art', as the phrase was understood when it was inserted into the Constitution.
The term is first recorded in the impeachment of of the King's Chancellor, Michael de la Pole, in 1386.
At the time the Constitution was being written and edited there was a famous impeachment trial going on involving the Viceroy of India.
So, the impeachment of Warren Hasting ran from 1786 to 1795, while the Constitution was being debated and was the "trial of the century" of its day. Everybody talked about it.
At the time of Nixon's impeachment Peter Rodino commissioned a staff report on the history of impeachment including the meaning of this phrase.