But if Dershowitz or his research assistant had done just a few minutes' more work, they would have learned ...
The Senate is "sole judge" of impeachments, it can use any standard it wants

Once again, Dershowitz's sources say the opposite of what he says they say.
In 2019, soliciting a bribe *is* a federal crime. As GAO ruled, it's illegal too for president to hold funds voted by Congress.