Bitcoin is Bitcoin, Trump is Trump and Bitcoin will be in charge for a longer time than Trump will be in charge as a President of the USA. Don't mind about him too much, no matter what he does, he will leave the White House after next four years. He can do good things and bad things for USA citizens and Bitcoin community, but he will not be able to harm Bitcoin too much.
Doubt, if Trump Bitcoin is illegal, I can't imagine how the market would react.
It will be a domino effect, EU will follow, and other countries will follow too. Then, the countries who accept Bitcoin will be sanctioned because The US think every decisions they make are correct, others are wrong.
Bitcoin price depends on the market and the market not yet ready with decentralization, they always believe in big people or institutions.