CAN-SPAM doesn't apply to political e-mails, Ron Paul SPAM?

I was further researching "Ron Paul SPAM" and found mention that political e-mails do not fall under the CAN-SPAM law.


"Savvy politicos know that CAN-SPAM and other anti-spam legislation don't apply to them… but they follow the laws anyway, as if they did."


If such is the case, then why hasn't this been questioned before?