✅ Election by bribery/corruption
✅ Profiting from office
✅ Obstructing Congress
✅ Abuse of power
Trump is an un-indicted, co-conspirator in a federal case where people have gone to jail for helping him silence witnesses who would have harmed his chances of being elected.
Trump has violated the Emoluments Clause.
He has refused to divest from his businesses, has all but required the government to spend tax payer dollars at his resorts, and encouraged electeds, lobbyists & foreign govs to stay at his hotels.
Trump has instructed witnesses not to comply with congressional subpoenas and has instructed federal agencies not to produce documentation, violating well settled constitutional law.
There's a lot here. But, an impeachable offense the Founder mentioned in particular was the abuse of pardon power. Trump has dangled pardons to those who could implicate him in order to undermine criminal and congressional investigations.