Not in the US--it's pretty rare for a full time employee to have some kind of contract that retains their employment. In fact in a lot of states employment is considered 'at will' and you can be let go at any time for any reason (or no reason!). The big exception is if you're a 'protected class' like certain races, above a certain age, etc. but that just means the employer has to prove they didn't fire you because of that protected class.