Trump clearly does his dirty business orally, which suggests he knows it was wrong.
The evidence will be numerous people indicating that this is his practice. As well as Cohen's recordings of conversations, which I imagine he made for self-preservation purposes. He knew his client was dirty and he prepared himself for a future plea deal. Oh, and it turns out that Cohen's current account of the history is confirmed by email records between Cohen and a third party, probably the mysterious Felix Sater. I imagine he is part of Mueller's programme as well.
So ... Trump appears to have directed a criminal conspiracy to make money for himself from his participation in the election and from winning the presidency. He sold America to Russia for several hundred million dollars.
Jail is warranted. For him and his group of conspirators. Massive sanctions for Russia.