If your email inbox starts overflowing with messages from political campaigns this election season, it could be because your state sold you out.

A Fox News study has found 19 states plus the District of Columbia, now ask for an email address on voter registration cards. In nine of those states, email addresses from the cards are then sold to political parties, organizing groups, lawmakers and campaigns who can use them to send unsolicited emails.

If it were a Viagra ad, it be considered a crime in some states. But a political message, that's all perfectly legal.

The CAN-SPAM (Controlling the Assault of Non-Solicited Pornography and Marketing) law enacted in 2003 puts restrictions on commercial mass emailing, but not on political mass emailing. Politicians can "spam" and do. Political messages of any kind, including electronic, are protected free speech under the First Amendment.