Most of the problems of spam have to do with who's an approved sender and who's abusive. Regulate the mail, it's much harder to be abusive.
You're in this country and sending spam? We arrest you. You're in another country? We rate limit your mail, report you to foreign authorities, and flag anything that looks like your mail.
You can burn me at the stake now.
But I also think there should be a government regulated digital 'town square' for each level of government, with township / county being optional but the rest funded by taxes. Then have those groups determine what is allowed and what's not, through people they nominate in elections. This is like the 'public option' for Facebook.
But mostly I just think this because I want more tax dollars to go to open source projects trying to solve problems that are very real and very much caused by the incentives of private industry.
If I am a website owner, no way I am going to use regulated service that will bring police to my door if I make a bug in my script, unless I have to.
Further laws around spam might help, but you don’t need the government to actually run anything for this.