What started as a joke post on the highly addictive link-sharing website Reddit has morphed into a reality that could alter the immediate future of US politics.

Jon Stewart's "Rally to Restore Sanity" and Stephen Colbert's "March to Keep Fear Alive" have so shaken up the political discourse in the US that the Washington Post today asked if comedy could save the United States. And, boy, does it need saving, according to the Post:

The United States of America isn't united any more; it's being torn apart by media-driven extremism . . . Democracy is the art of compromise; it requires that Americans who hold different views be able to develop enough empathy for each other so that bipartisanship can actually occur, and the country move forward. If we cannot cut each other any slack at all, democracy cannot function.

The tonic for this dysfunction is Stewart's upcoming rally. After months of hysterical, right-wing Tea Party-dominated reports, America's political discourse will undergo a calming change. Stewart's rally is not for the enraged minority, it's for the moderate majority.

We're looking for the people who think shouting is annoying, counterproductive and terrible for your throat; who feel that the loudest voices shouldn't be the only ones that get heard; and who believe that the only time it's appropriate to draw a Hitler moustache on someone is when that person is actually Hitler. Or Charlie Chaplin in certain roles.

Stewart is sometimes billed as the most trusted man in America. Often, his show is the only news programme on American television that toes a line between the extremes of Fox's right-wing evangelism and the browbeating liberalism of MSNBC. Stewart, however, has always been careful to disassociate himself from personal political activism. In a profile published just last week, he said candidly:

We're not provocateurs, we're not activists; we are reacting for our own catharsis . . . There is a line into demagoguery, and we try very hard to express ourselves but not move into, "So follow me! And I will lead you to the land of answers, my people!" You can fall in love with your own idea of common sense. Maybe the nice thing about being a comedian is never having a full belief in yourself to know the answer. So you can say all this stuff, but underneath, you're going, "But of course, I'm fucking idiotic." It's why we don't lead a lot of marches.

Except now Stewart is leading a march -- well, a rally -- and branching out into brand new territory. As the New York Times points out, the lines between politics and the media are becoming blurred:

Picture a football game where the reporters and commentators, bored by the feckless proceedings on the field, suddenly poured out of the press box and took over the game. In politics, it seems as if the media [are] intent on not just keeping score but also calling plays.

This trend started on the right. Palin has more influence now, as a Fox News Commentator (with a capital C), than she ever did as governor of a backwater state. Glenn Beck is just one of a handful of Fox News anchors -- such as Sean Hannity and Bill O'Reilly -- who use their shows as a pulpit to indoctrinate rather than inform.

The antithesis of these shows is provided by Stephen Colbert, the lampooner-in-chief of personality-driven news shows, such as Beck's. Colbert sends up their emotive, manipulative style to devastating effect on his spoof show The Colbert Report. (Imagine Brass Eye and The Day Today, but with higher production values, and produced every night.)

Colbert and Stewart have been fighting against the hysterical coverage of Fox News and figures like Beck and O'Reilly for years -- except now the game has changed. Figures such as Beck have taken to the streets. If Colbert and Stewart want to keep fighting for moderate, sensible news coverage, they will have to follow.

Duncan Robinson blogs here. You can also follow him on Twitter.