Robin Williams is killing. Bathed in a spotlight onstage at the TV industry's semi-annual showcase, the comic is keeping the packed ballroom rollicking with the stream-of-consciousness improv that has made him a cultural icon for several decades.

"It's sad. I mean 'W' is gone," he says of George W. Bush. "He was a gift to comedy.... Sarah carries on for him, though. 'Thank you Sarah.' I mean, how did they find her? 'Project Running Mate?' "

After a short film summing up Mr. Williams's contributions to American comedy since 1977, the affair turns to the serious matter of humor itself. "How would you say comedy in America has changed since you came on the scene 30 years ago?" comes a question from the back of the room.

"It's gotten more interesting," he says. "Politically, it's open season, man, thanks to Jon Stewart.... [T]here's so much to talk about every day."

Out of the mouth of one of America's top comedians comes the same assessment made by cultural anthropologists, historians, and academics who study humor. Comedy of all kinds is proliferating, from the genteel riffs of Ellen DeGeneres to the R-rated barbs of Chris Rock.

But after decades of life on the fringe, political satire – material riffed on and ripped from the news – is becoming the lingua franca of American humor. Topical humor is now the standard rather than exception – it is the sandbox for a new generation of performers in comedy clubs, for the punch-line potentates on cable TV, for the growing legion of late-night talk-show hosts.

"It's being normalized, bringing not just punch lines or gags, but true political satire into the mainstream of American comedy," says John Morreall, a humor expert at the College of William & Mary in Williamsburg, Va.

Behind the shift is a combination of timing, talent, and technology. Experts attribute the rise to the emergence of some gifted comedians (led by political satirists Mr. Stewart, Stephen Colbert, and Bill Maher), alongside an administration that Hollywood considered ripe for skewering (Bush/Cheney), coinciding with a younger generation that is turning away from newspapers to comedians for news.

At the same time, broadband has given the masses the ability to swap their favorite video clips of everything from late-night monologues to local comedy acts. This has fueled the rapid expansion of Internet comedy sites such as YouTube and FunnyOrDie.com and a hunger for immediacy. The 24-hour news cycle provides the perfect pantry from which to feed this voracious appetite.

"Modern America can't escape the news – it's even on a digital readout while you're standing in line at the bank," says Nina Tassler, head of programming at CBS. "It's only natural that entertainment would reflect and comment on that."

Since humor provides a window into the nation's soul, the rise of headline comedy says a lot about who we are at the moment. Certainly the ability to laugh at our political leaders, and by extension ourselves, is a sign of a healthy society. Some comedians even get more grandiloquent about it than that: They see the purveyors of today's headline humor as not only providing entertainment, but also incisive social commentary at a time when the real media increasingly can't or won't.

Yet others see the nightly guffaws about Sarah Palin's IQ and Barack Obama's ears adding to the cynicism about government, turning the nation of Jefferson into a nation of smart alecks. In the end, is all this laughter helping us become more politically sophisticated or more superficial?

TO ILLUSTRATE THE "normalization" of news-based humor, look no further than the three-decade journey of "Weekend Update," the segment on "Saturday Night Live," in which comedians sit at an anchor desk and satirize the week's events. The sketch, pioneered in the 1970s, is the longest-running recurring segment on "SNL." But it has always been just one sketch on the show, which airs late Saturday night. For this fall, NBC has ordered six episodes of the fake news show for its prime-time lineup on Thursday night.

The move by Jay Leno to prime time (10 p.m.) Sept. 14 for a full hour of nightly comedy also underscores the rise of headline humor. His show will come complete with comedian D.L. Hughley as a Washington-based "political correspondent" and regular updates from actual NBC news anchor Brian Williams.

Or, if you need a third example of the ubiquity of satire today, consider the evolution of comedians entertaining US troops. As part of his USO tour in 1968, Bob Hope performed at Cam Ranh Bay in Vietnam, accompanied by singer/dancer/heartthrob Ann-Margret, Miss World Penelope Plummer, and the Golddigger Dancers in miniskirts.

Mr. Hope didn't veer much into the politics of the war, in part because he was an ardent supporter of it. But even if his stance would have been different, the war was not a topic you broached blithely at the time: Don't forget that CBS canceled "The Smothers Brothers Comedy Hour" in the late 1960s – when it was the No. 1 show on television – largely for being too critical of Vietnam.

Contrast that with Mr. Colbert's recent trip to Iraq. The war was almost his entire shtick. At one point, he interviewed Iraq's deputy prime minister, Barham Saleh, onstage. "Bob Hope's material stayed far away from the realities of the Vietnam War," says Robert Thompson, founding director of the Bleier Center for Television and Popular Culture at Syracuse University in New York. "But Stephen Colbert kept it onstage at all times."

In part, the headlong dive into news- and politics-based humor represents simple pragmatism. With so many late-night talk shows and comedy programs on cable TV, performers need a rich sea vent from which to get their material.

As 50-year comedy veteran Bob Newhart puts it: "Television is an insatiable beast that must be fed" by writers who "pore through news reports for the tiniest tidbits to keep their material fresh."

Yet to appeal to a mass audience, comedians also need to speak in a universal language. "For their own survival, comedians are trying to reach the broadest and most diverse audiences," says Mr. Thompson. "They need to focus on what is the most shared aspect of everyday life and that, increasingly, is the news."

America, of course, has explored this territory before. Political satire thrived during the American Revolution – in print, onstage, in the public square. Gradually the genre dropped away here while European countries entered a great age of caricature and political cartoons in the 1800s and 1900s.

"Americans are much more passive and much less politically aware [than Europeans]," says Professor Morreall. "Americans tend to go along with things, until they hit a breaking point like the Vietnam or Iraq war."

The modern form of political- and news-based comedy is rooted in the late 1950s. People like comedian-actor Mort Sahl tapped the day's headlines for their routines. Mr. Sahl would actually appear onstage with a newspaper tucked under his arm.

Jack Paar, Johnny Carson's predecessor on "The Tonight Show," dabbled in topical humor, while Lenny Bruce, the stand-up comedian and satirist, took social criticism to a much edgier level, eventually being arrested for violating obscenity laws.

In the late 1960s, there was the Smothers Brothers, and, in the 1970s, the shift of political humor away from talk shows (with the exception of Johnny Carson) to sitcoms like "All in the Family" and "M*A*S*H."

In 1989, Time Warner (owner of HBO) launched the first all-comedy cable channel, marking a hinge moment in the history of humor. It provided an outlet free from the constraints of broadcast TV. Seven years later came "The Daily Show," a self-described "fake news show."

The timing was impeccable. When Stewart took over in 1999, the Clinton impeachment – and his artful denials – were at their peak, providing ripe material to spoof. This was followed by the election crisis of 2000, with its "hanging chads," and eventually the US-led invasion of Iraq. Comedians pinpricked Mr. Bush throughout his presidency.

"It was the perfect type of government for comedy to thrive in," says Morreall. "There was quite a bit under Clinton and a fair amount under Reagan, but it never 'normalized' until Bush/Cheney."

Now mirthologists think the next natural step in the evolution of headline humor is prime-time shows like Mr. Leno's. Already there's evidence of the genre's popularity: strong ratings for Leno's most recent program, as well as for Conan O'Brien's, Jimmy Fallon's, and for "Saturday Night Live." "What we're so excited about is how important topical live comedy is right now," says Ben Silverman, former NBC Universal Entertainment co-chairman, who spearheaded moving Leno to 10 p.m. "All our research showed that America wants more comedy."

As topical humor has become more pervasive, its tone and content have become bolder and at times coarser. Cable TV and the Internet have contributed to the freer – and fouler – voice.

Consider these two bookends in the genre's evolution: After John F. Kennedy became president in 1961, Sahl started making jokes about the administration's policies. But television host Ed Sullivan, whose prime-time show was one of the few outlets on TV for comedians, wouldn't let Sahl do any jokes about the president, even though Sahl had actually done some speechwriting for Kennedy.

Now fast-forward to the 2006 White House Correspondents' Association dinner, where the featured entertainer was Colbert. In his typical in-your-face style, he unleashed a comedic diatribe about Washington, including President Bush, who was sitting a few feet away. "A lot of people compare this administration to the Titanic," said Colbert in his mock conservative-defends-the-president outrage. "I say nooooooo, it's the Hindenburg.... It soars."

At least some boundaries on how far comedians can go remain in place, particularly on broadcast TV. David Letterman got in trouble this year – and apologized – for making sexual-based monologue references to Sarah Palin and her family.

Sensing perhaps a saturation of headline humorists, some comedians are trying to avoid becoming just another dissector of the news. Brad Garrett, the comedian best known for playing Robert Barone on "Everybody Loves Raymond," has developed a shtick he calls "personal politics" – not culled from the news – for his 40 gigs a year in venues across America. "Bill Maher and Colbert and Stewart are brilliant comedians because of their gift for telling it like it is and making news more digestible," says Mr. Garrett. "Do I think we need more of it? No."

Scottish immigrant Craig Ferguson, who hosts CBS's "Late Late Show," uses puppets, monologues, and skits with outrageous hats, costumes, and makeup. While he'll touch on political topics, he tries not to be caustic on certain subjects. America, for him, is "a flag and an ideal," he says. "It's a dream. I have difficulty playing with that in any kind of iconoclastic way on the show because it's such an important thing for me."

ALL OF WHICH raises a deeper question: If we're moving into a golden age of satire, which some people think we are, is it good or bad for society? Americans do seem to be laughing more – or at least should be. That's because there are so many more outlets for comedians today – more late-night talk shows, more comedy clubs, more cable TV channels, and, notably, the Internet.

Comedian Drew Carey notes that Larry the Cable Guy, the stage name of stand-up comic Daniel Lawrence Whitney, whose redneck character has a huge following online, made $21 million in 2006 "and that was just his road money." Thanks to the Internet, "now you don't have to trudge over to the Playboy Club and try to get your 20 minutes on stage," says Mr. Carey.

And the country that laughs together, in theory, stays together. "Humor has played a very particular role in American culture," says Joseph Boskin, a history professor emeritus at Boston University. "We are a fractious, diverse, multiethnic society, and unlike other, homogeneous cultures, humor has played a much more prominent role in helping us cohere, in actually keeping all these parts from just flying apart." He thinks today's political satire promotes "awareness and engagement."

Some in the industry agree it engenders more than just laughs. "Colbert and Stewart are the most important comics right now," says veteran comedic actor John Lithgow. "They are incredibly important to the body politic. When I think about newspapers failing and important journalists looking for paying work, I think 'thank God at least Jon Stewart is there.' Our whole society depends on people having skeptical intelligence."

Carey goes one step further, pointing out the vital role humorists have always played in pushing the limits of free speech and challenging the status quo. "American comedy clubs are the last places where you can say what you want and say what you feel," he says.

Yet not everyone is ready to canonize comedians as the saviors of American democracy (what's next, electing one to the US Senate?). As early as 1985, social critic Neil Postman, in his work "Amusing Ourselves to Death," worried about the erosion of public discourse in the era of television. While his critique wasn't aimed at humor, many see parallels to the current din of news-based comedy.

If we turn too many politicians into cartoon characters and if young people get their news from monologues – which polls today show they do – doesn't this affect our worldview? "We should be very worried about the cynicism this satire engenders," says Brent Bozell, president of the Media Research Center in Alexandria, Va. He, in fact, maintains that issues don't enter the public consciousness "until they are a joke on late-night shows."

That, of course, is a comment about us more than any comedian. Once again this summer, a poll, this one of Time.com users, found that Stewart is the "most trusted newscaster in America." This horrifies no one more than Stewart, who always reminds people that what he does is "fake news."

Others worry that as political humor becomes more prevalent, it will also become more polemical, further dividing the nation. Many comedians, to be sure, are equal opportunity offenders. Yet some in the industry would like to see more parodying of the political class the way Will Rogers did it in the 1920s, in a nonpartisan way. "Real comedy should be daring enough to cross party lines, because the truth doesn't live on just one side," says Cary Odes, who teaches stand-up comedy in Los Angeles. "A comic's job is to pry up the floorboards of our preconceptions and show what's really going on beneath us."

Ultimately, the tenor and amount of political satire coming into our living rooms and iPhones may be self-regulated. On the Dean Martin roasts of the 1960s, one of the biggest staples was one-liners about drunkenness. But as the dangers of alcohol became more prevalent, drunk jokes diminished. If headline humor were to become too caustic, one-sided, or omnipresent, it may receive the ultimate rebuke – the sound of no one laughing.

In the meantime, everyone may want to sit back and enjoy it. As Mr. Newhart reminds us: "Comedy allows you distance in a difficult situation. It allows you to face something directly and move on. Without it, we'd be curled up in a fetal position in a dark room."

How comedians skewer politicans around the world

Combine comedian Jon Stewart with impersonator Rich Little and a touch of the Queen's English and you've got Rory Bremner, a quick-witted British comic who specializes in tweaking powerful political figures both at home and abroad.

His spot-on impersonations of everyone from British Prime Minister Gordon Brown to Bill Clinton and George W. Bush place him firmly in the English tradition of performers using the pointed barb of satire to shed a different light on the news.

In fact, over the centuries, virtually every country has evolved its own variation of the tradition of people speaking truth to the powerful by cloaking their swords in the costume of the clown.

"The use of satire to skewer politicians and corporate interests is a universal phenomenon we can find deep in history," says Jack Lule, a global cultural expert at Lehigh University in Bethlehem, Pa. He points to contemporary examples as diverse as Italy's Beppe Grillo, an activist-performer who has been dubbed the "clown prince," and Malaysia's Zunar, a political cartoonist and founder of the satirical magazine Gedung Katun.

Countries such as Egypt, which have tried to control traditional media, have witnessed an explosion of politically barbed comedy on the Internet. The Egyptian satirist Magdy Saad, whose blog Yalla Mesh Mohem ("Who Cares?"), routinely tweaks Egyptian leaders, was arrested this summer. Comedians are penning and performing their spoofs elsewhere in the tumultuous region, too. "Both the Palestinians and Israelis have made some attempts at using humor to make a point, and even to heal," says Michal Ann Strahilevitz, a marketing professor at Golden Gate University in San Francisco. One example: "West Bank Story," a short musical comedy based on West Side Story's classic Romeo and Juliet theme, except in this case it's Palestinians and Israelis with warring falafel stands.