A lot of people probably didn't know that Congress has to power to impeach any public official, not just presidents, if they are found to have committed high crimes and misdemeanors. One of the reasons this fact is so obscure is that it happens even more rarely than the impeachment of presidents. The last time it happened was in 1876. And it makes sense that it would happen rarely, because normally if a public official has done such things, the Justice Department would bring its own charges and no action by Congress would be necessary.