Have the US Post Office begin selling/issuing various classes of digital certificates that are required for use with a new, secure email system. If someone is found to use such a certificate for an unauthorized purpose then it could be revoked, and it would instantly no longer be able to send emails.
End users would then be able to block or filter emails by sender, class of email, size of email, etc.
The new “professional” email protocol would be “smarter” than the current email protocol in that, if an email did not meet the recipient’s criteria, it would never even consume Internet bandwidth (another money-saver).
The analog between this new class of email and the old standard would be similar to amateur vs. CB radio.
Revenue would be generated through sales of the digital certificates (which would have to be periodically renewed). The Postal Service would be energized with a new, modern purpose (and, since providing a person/business with a digital certificate should require verifying their identity in person, the USPS infrastructure would be critical), and emailers throughout the world would be supportive because email SPAM would have become a thing of the past.
Location: Tampa, FL