The law banning pot is a federal law. The fed does not have the power to make that law. They only have the power to make it illegal to transport pot across state lines.
As for firing them, you have the power to fire your congressman, senator an the president for any reason you want. But not the other congressman an senators. They don't work for you.
Gah,.. i'm confused, as usual..

All i know is, in MA, if you get caught with it... or caught selling it... you can be really screwed.. again depending on the amount you are caught with..
You mean i cant fire other states congressmen or senators?? If so, yes, i kinda already thought that...it would be the residents/voters of each state to do that..? No?