Would you pass a law restricting what you could do to get yourself elected?

Of course not.

The person could not pay your ISP to do it. However, they can buy lists from information brokers and send out mail to all the e-mail addresses that they get that way. It is kind of like junk mail in you mail box. If you do not like, delete it.

There is a law called the can spam act. Google it. The person must opt in to the mailing, it must have an option to unsubscribe. If you unsubscribe they can not email you anymore