This entire topic rests on a false assumption. The Democrat Party can’t be outlawed, because there is no such legal status as “domestic terrorist organization”. Individual terrorists can and should be prosecuted, but it is impossible to ban an organization in the USA. The freedom of association means anyone has the right to be a member of any organization he likes, regardless of what crimes other members have committed. Only foreign organizations can be designated as “foreign terrorist organizations”, and even in those case it is only a crime to give them material support, not moral support.