Although this is true for at-will states, if you get fired you can still sue for wrongful termination. It will still be up to the company to prove that you were NOT fired for actionable events (such as being female, or gay, or asian, etc). Most smart companies (HR specifically) will fire you with NO REASON thus if you sue, they just have to prove you were not fired because you were female or black or whatever. If they fire you for A REASON then when you sue they ALSO have to prove that reason. So if you're fired because you show up late, and they state that in documentation, when you sue, they have to PROVE you were late and notified of being late, etc. with documentation of the infractions. In a lot of companies, if you are fired, there is NO REASON given. You might be told you're fired because you're late, but the documentation does not list a reason, thus helping the company in the event of a lawsuit.