“The mistake in the Clinton impeachment in 1999, was that the Republicans went after him for private conduct”
It wasn’t private conduct.
Using the authority of your office to gain sexual favors from staff members is by definition sexual harassment in the workplace, the very issue for which he was being sued in federal court. He lied about this conduct to a federal judge in order to impede a civil rights lawsuit, and this was public conduct.
For this, Bill Clinton became the second president to be impeached.
It wasn't a "mistake" either; it was quite deliberate.
The idea that the Government can define consensual conduct between adults as "sexual harassment," because of a Feminist theory that demonizes male advances, does not change the issue. (Now, do not get this wrong. When Bill Clinton exposed himself in a public setting, as an intended come on, he should have been arrested for lewd behavior, and taken into custody. That is not the Monica issue.)
But my point was really neither of those. The point of Abuse Of Power, was that Clinton should have been impeached for a very clear dereliction of his public duty; that his actions using his position of "Commander In Chief," to push an asexual agenda in the Military, at the expense of the effectiveness of that Military was indeed a grounds for impeachment. One many times more serious than simply yielding to temptation in private.)