Sometimes laughter really is the best medicine. In America's angriest political landscape in living memory, where bickering lawmakers pursue self interest ahead of the public good and the corridors of power resound to the word "no", one public figure proved this week that he stands alone in his capacity to get things done. He is Jon Stewart: comedian, host of The Daily Show and the country's unofficial satirist-in-chief.
Two months after enticing roughly a quarter of a million people to his "Rally to Restore Sanity", and a month after a poll pegged him as the "most trusted figure" in TV news, Stewart, 48, has successfully concluded a campaign to steer a piece of legislation called the James Zadroga Act through the US Senate. In doing so, he scored a signal victory against Republican members of the highest legislative body of the most powerful nation on earth.
The coup cemented Stewart's position as the nearest thing liberal America has to a head rabble-rouser and saw him lauded by The New York Times as today's reincarnation of the crusading reporters Edward R Murrow and Walter Cronkite. In the internet era, the newspaper argued, his ability to carry public opinion and exert genuine influence on the political process proves that "comedy on television, more than journalism on television, may be the most effective outlet for stirring debate and effecting change in public policy".
It's difficult to say whether Stewart now has as much clout on the left of America's political spectrum as polemicists such as Rush Limbaugh and Glenn Beck boast on the right. But he certainly reaches a sexier demographic. While the average viewer of Fox News is in his seventh decade, fans of Comedy Central, The Daily Show's cable channel, are mostly under 40.
Online, viewers are younger still. And that's where Stewart comes into his own: his rapier wit and command of high and low culture might have been custom-designed for the internet. So he gets a relatively modest 1.3 million viewers, in a nation of over 300 million, on TV, but internet viewers magnify his reach exponentially.
Not only is Stewart's left-leaning take on current affairs easily digested into YouTube-length clips, it is also perfect fodder for influential websites such as Gawker and the Huffington Post, which stream those clips almost daily. In effect, this has made him the Crown Prince of gotcha journalism, 2.0.
"Because of technology, the difference between entertainers and politicians has never been less than it is now, and Jon Stewart is at the forefront of that," says Paul Levinson, the media don and author of the book New New Media.
"The explosive growth of handheld devices means that watching a clip of him has become as easy as it used to be to glance at a newspaper article, perhaps even easier. Although he's a comedian, what he says is now getting reported as news. Two or three times a week, MSNBC will talk extensively about one of his monologues. He's actually setting the agenda."
Stewart's strength has never been more starkly evident than during his coverage of the Zadroga legislation. The saga began when he angrily observed that Republican senators planned to filibuster a bill to create a $4bn fund for New York emergency workers who picked up serious illnesses inhaling toxic dust after 9/11.
Republican hostility to the fund, rooted in a knee-jerk antipathy to legislation which takes money from corporate America and gives to a public healthcare programme (it was to be financed by closing a tax loophole exploited by large companies), was lambasted by Stewart no less than four times this month.
He used segments of the show to dub the senators "Worst Responders" and highlight the hypocrisy of their previous support for first responders who had heroically volunteered to clean up after the worst terrorist attack in history.
His last programme before Christmas was then devoted entirely to the issue. He criticised the "disgusting" and "outrageous abdication of our responsibility to those who were most heroic on 9/11". He called it a "national shame" during a hard-hitting interview of four terminally ill former Ground Zero emergency workers who are yet to receive a penny in compensation almost a decade after the attacks.
And then something amazing happened: amid growing public outrage, sparked by Stewart's reports, the Republican "filibuster" vanished. The party's senators performed a remarkable volte-face and, last week, the Zadroga Act duly passed. Stewart, who championed the issue when barely any TV news programme or US newspaper had so much as mentioned it, was therefore credited with a single-handed political coup.
"Jon shining such a big, bright spotlight on Washington's potentially tragic failure to put aside differences and get this done for America was, without a doubt, one of the biggest factors that led to the final agreement," was how New York's Mayor Michael Bloomberg, who had supported the bill, put it.
So where does this leave Stewart? In the short term, it gives him a minor PR problem, since he has always maintained, against all available evidence, that he has no political clout, and should not therefore be described as a journalist. He even told the placard-wielding hordes at his rally in October that it was "not a political event in any way, shape or form".
Now, of course, Stewart's influence has been laid bare for all to see. After almost 11 years at The Daily Show, he must face the consequences of exerting that influence, good and bad. He may be a professional funnyman but he also now carries a burden of responsibility.
"Jon Stewart isn't just a comedian. Even though he styles himself as such, and keeps telling everyone 'I'm not a politician', he's overtly political in a lot of what he does," says James Rainey, a media commentator for The Los Angeles Times. "It's now obvious to everybody that he has a lot of power and some very bright people behind him."
The affair makes ugly reading for other US journalists, since it illustrates a disturbing malaise affecting America's declining traditional television and print news. The Republican effort to quietly prevent national heroes from getting proper medical care was a newsworthy story with widespread appeal. Yet it was entirely ignored by all of the network TV news shows and most major newspapers.
"How can you not be for heroic police and firefighters?" says Rainey.