not completely since in some it is legal but in a medical way whereas at the moment there are 8 states in which the cultivation, consumption and commercialization of this is allowed. On the other hand the other 42 states are in similar situations but with many nuances which have not been decided.
Technically marijuana is illegal in all 50 states under federal law. The local police may not chose to enforce the law but any federal DEA agent can make a drug arrest, even in a state that "allows it".
Marijuana is classified by the U.S. government as a schedule 1 drug which means the U.S. government does not believe marijuana has any medical value and is likely to be abused as a drug.
No, a lot of states it is still illegal. many states have adopted the medical use of cannabis and also a few states have made recreational use of cannabis legal.