If you are not employed by a public employer and work for a private company, and if you are not represented by a labor union and have no contract, then it is legal in Indiana to fire you because of your politics.  You can be fired because you attended an anti-Trump protest rally, or because you attended a rally supporting Trump.  Other states have laws that protect employees from being fired for what they do outside the workplace.  Indiana does not.  For an article about this issue, go to the link below.
https://www.linkedin.com/pulse/how-your-boss-can-legally-fire-you-attending-protest-phillis-rambsy