So if a majority of states wish to ban certain newspapers, then the federal government can ban them, in spite of the "Congress shall make no law" language of the first amendment, because otherwise they could be smuggled from neighboring states? Seems like a very strange version of federalism to me.
No. Because the first amendment says, "Congress shall make no law ...". It's right there. Plain as day.
Did you see something that said Congress cannot prohibit the interstate commerce of machine guns? They've been doing that for over 70 years and no one's caught it yet.
But, wait! YOU found something?!?!