Liberal US funnymen Jon Stewart and Stephen Colbert hold a mass rally in Washington Saturday billed as an antidote to the ugly political mood polarizing America in the run-up to mid-term elections.

The Rally to Restore Sanity and the March to Keep Fear Alive are expected to draw over 100,000 participants to the National Mall in Washington, just three days before Americans go to the polls at the end of a bitter election campaign.

Although organizers insist it is non-political, many see the rally as a liberal response to the ultra-conservative Tea Party movement, which has held events across America to oppose what it views as growing government intrusion.

Right-wing radio talk show host Glenn Beck appalled liberals in August when he hosted a rally "to restore honor" on the anniversary and at the site, on the Mall, of Martin Luther King's famous "I have a dream" speech.

At least 80,000 people -- hundreds of thousands according to organizers -- turned out to Beck's rally to show their opposition to President Barack Obama and what they call his administration's big government or "socialist" policies.

Two weeks later, Stewart and Colbert, considered two of the funniest men in America thanks to their primetime political satire shows on Comedy Central, announced twin rallies on the Mall which were later combined into one.

The name "The Rally to Restore Sanity" is an unabashed dig at Beck's event.

The organizers of Saturday's event are billing it as a 21st-century version of the Woodstock music festival held in upstate New York in the midst of the Vietnam War, "with the nudity and drugs replaced by respectful disagreement."

"The focus of the rally is the ugliness of political debate: the Hitler comparisons, the head-stomping, the conspiracy theories, the assumption that your opponent is also your enemy and must always be assumed to be acting in bad faith," James Poniewozik said in an article in Time Magazine.

He was referring to posters at Tea Party rallies depicting Obama as Adolf Hitler and a recent incident at a campaign event in Kentucky when a liberal activist was pushed to the ground and stepped on by a Tea Party supporter.

Eileen Robinson wrote on the rally's Facebook page that she will be carrying a sign on the Mall that reads: "I'm a pro-life Democrat but I'm pretty sure that doesn't make me Hitler."