Certainly it would unconstitutional to legalize suicide drugs for only these few. It would have to be open to every American citizen in every state, wouldn't it?
That's more than 50. And that's how the USSC would look at it (as they did in Wickard v. Filburn).
"One might think ahead to an anti-death penalty Congress that seeks to outlaw the death penalty in the states by using its interstate regulatory power to prohibit the use of electricity, drugs, gas, rope, guns, etc., for any purpose that leads to the death of a human being."
Well, they can always try. But they do answer to the voters, don't they?
"(The Second Amendment reference referred to the Constitutions explicit granting of the people's right to keep and bear arms. Could Congess, using its interstate regulatory power, prohibit the use of guns to kill deer?)."
Congress has used the interstate Commerce Clause power in the past to regulate guns -- the short-lived federal AWB was implemented this way. I can see how the federal government can ban a class of weapons this way, but not its application.
A better way would be to declare deer an endangered species, yes?