Colo. Rev. Stat. § 13-21-106
The owner, licensee, or operator of a visual or sound radio broadcasting station or network of stations and the agent or employees of any such owner, licensee, or operator shall not be liable for any damages for any defamatory statement published or uttered in or as a part of a visual or sound radio broadcast by one other than such owner, licensee, or operator, or agent or employee thereof, if, in any action brought to recover such damages, such owner, licensee, or operator, or agent or employee thereof, alleges and proves that he exercised due care to prevent the publication or utterance of such statement in such broadcast; except that, in no event shall any owner, licensee, or operator, or the agents or employees thereof, be held liable for any damages for any defamatory statement uttered over the facilities of such station or network of stations by any candidate for public office or by any other person speaking for, or on behalf of, any candidate for public office where, by any federal law, rule, or regulation censorship of such political statements in advance of such utterance or publication is prohibited.
C.R.S. § 13-21-106