Can an employer interviewing someone for a job, ask who they voted for and make their hiring decision based on the answer?
Can an employer fire anyone who supports Trump and it’s known in the workplace? (assuming the boss is a lib)
The answer to each of those is yes... if the employer enforces that rule consistently across all of his employees. Based on the law, you are free to discriminate against political parties. I know, I was shocked when I learned that too.