Make them fire you. If you resign under pressure you have basically no legal standing. Make. Them. Fire. You. If they pressure you to resign, you should write a letter, declining to resign, declining to take any responsibility for your private, off-duty, speech and/or actions. Specifically point out that you are exercising your personal discretion to engage in political and social commentary regarding current events, that you are not willing to be subjected to a hostile work environment for your unorthodox political views, and that you are not willing to explain or defend or justify those personal political views.
Always make them do their own dirty work.