But "at will" means you can be fired for any reason
except if the reason is "being in a protected class". Those include pregnant women, for examples.
It is so ridiculous it is funny. In the US, the law guarantees NO paid maternity leave, but you can't fire a pregnant lady. So, as soon as she gives birth, you can stop paying her (but not fire her), and then, two weeks after she comes back from maternity leave, you can fire her (because she is no longer in a protected class). So, basically, all this protection amounts to is ... about two extra weeks of severance.
US is pretty sad when it comes to labour law and employee rights - and most people living in the US are somehow under the illusion that it is better for them.
Does anyone know if sexual preference or sexual orientation is a recognized protected class?