There's no law against a private business deciding that they don't want to do business or offer their services to a person based on their inclusion in a non-protected class.
Political affiliation is not a legally protected class in the United States. Any business can choose not to do business with a Trump supporter, a republican, a democrat, a communist, or any other political affiliation because it is not illegal to discriminate against someone based on their political affiliation.
'Being Donald Trump' is also, unfortunately, not a protected class.
Real, legal answer?
There's no law against a private business deciding that they don't want to do business or offer their services to a person based on their inclusion in a non-protected class.
Political affiliation is not a legally protected class in the United States. Any business can choose not to do business with a Trump supporter, a republican, a democrat, a communist, or any other political affiliation because it is not illegal to discriminate against someone based on their political affiliation.
'Being Donald Trump' is also, unfortunately, not a protected class.