David Letterman delivered a fiery rant against CBS and parent company Paramount for cancelling Stephen Colbert’s “Late Show,” calling the decision “gutless” and “pure cowardice” as he labeled his successor a martyr of the network.

While “The Late Show” host Stephen Colbert was on his usual mid-summer vacation earlier this month, CBS executives weighed the pros and cons of canceling the unique but unfortunately unprofitable show.