States cannot violate due process laws because?

States cannot violate due process laws because it is unconstitutional. The fifth and fourteenth amendments both include due process clauses. In essence, due process is the fair treatment entitled to a citizen. For instance, a person cannot be sentenced to a punishment immediately, they have to right to go to court and defend themselves. Hope this helps!

It would be unconstitutional to violate the due process of law. 

Good luck: )

Ummm they were radical