It was 15 years ago, on Oct. 15, 2004, that the then-Daily Show host called Crossfire co-hosts Tucker Carlson and Paul Begala "partisan hacks" while criticizing the state of cable news journalism. "Stop hurting America," Stewart pleaded. CNN canceled Crossfire three months later, citing Stewart's rant. Stewart's emotional appearance on behalf of 9/11 responders on Tuesday reminded CNN TV critic Brian Lowry of his Crossfire moment and its significance. "Stewart's Daily Show tenure contributed to the understanding that comedians could do more than just 'be funny,' providing compelling voices in exposing media excesses, especially in those places where the theater of it all becomes indistinguishable from the news," says Lowry. ALSO: Jon Stewart isn't the only comedian who is helping to redefine patriotism.