Several readers have clarified. For example:

Calls from political organizations are not covered by the law. It’s nice that politicians exclude themselves from the restrictions they put on “evil”
businesses.
“Some calls, however, such as those from political organizations, solicitation calls on behalf of charities, and calls to conduct surveys, are not covered by the National Registry requirements. Consumers who sign up for the registry may still receive these calls.”
-http://www.ftc.gov/opa/2003/06/donotcall.htm

ME: Of course, as a matter of principle it would in fact be worse if the government could block political speech because it’s inconvenient.