“Incitement” is a loaded concept, easy to abuse, and easy to weaponize against the freedom of speech.

Incitement has a specific legal meaning, which is narrow. But impeachment is a political process, not a criminal one. Senators will not send Donald Trump to prison. They instead have the power to bar him from ever holding federal office again. (I defer to Ted Cruz on the constitutional issue of whether Congress may convict a former president in impeachment proceedings.)