[Sacajaweau]

We have a system called Impeachment to deal with "high crimes and misdemeanors" while in office. The Senate did not vote to remove him after either impeachment.

Why do any of these court cases exist?

[Theoria]

Impeachment isn’t designed to do that. Congress isn’t a criminal court, and Treason, Bribery, or other high Crimes and Misdemeanors should be dealt with like any other situation in court. Then after a conviction, Impeachment would handle the removal of a president, vice president, or civil officer. Impeachment without a criminal conviction is a mere political act at best.