WASHINGTON » He has all but called them losers and fools, but when Jon Stewart announced Tuesday that he would leave "The Daily Show" sometime this year, many politicians and news media personalities had something of an unusual reaction: grief.

"When he gives me a hard time, I understand that I’ve arrived," said Sen. Lindsey Graham, R-S.C., whose recent announcement that he was considering a run for president sent Stewart into a fit of sarcastic ecstasy. "Thank you, Jesus!" Stewart cried as a six-person ensemble marched onstage playing "When the Saints Go Marching In."

Stewart went on to call Graham, a foreign-policy hawk, "delusional," but the senator said Wednesday that he harbored no ill will.

Does Graham ever feel offended? "No," he said. "I’m going to try to go on that show before it’s over with."

Graham’s response is a perfect example of the kind of conflicted sentiments that Stewart’s favorite targets often express. The joke may be at their expense. But they’re laughing nonetheless. In interviews, some of the politicians and journalists who found themselves in Stewart’s commentary talked with fear and admiration about his ability to shape, create and tear down popular perception, especially among younger voters. And they said they knew that if Jon Stewart skewered them, they mattered — even if they might wince a little at what they heard.

He could be their most powerful critic and tormentor, but he was no mere satirist. One of Stewart’s favorite bits is to mimic Graham’s South Carolina lilt as he rips his tendency to deliver dire, alarmist warnings on terrorism and security. "The poor man lives his whole life trapped in ‘The Blair Witch Project,’" Stewart once said on the show.

"A point made through humor," Graham said, "is often the best-delivered point."

Like much of his audience, Stewart’s subjects seem to view him not as a comedian but as a legitimate newsman — without the usual qualifiers like "faux" or "entertainment."

Sen. Charles E. Schumer, D-N.Y., said that when he wanted to promote the Democrats’ plan to offer lower-cost student loans last summer, there was one television show he wanted to do.

"It’s top two or three in terms of influence on public opinion — and with young people, he’s probably No. 1," Schumer said.

Schumer, who like Graham has also found his voice the punch line in Stewart’s jokes, was rather self-aware when asked what it was like to be on a joke’s receiving end. "We are who we are," he said. But, he added, "I don’t realize the extent of my Brooklyn accent until he imitates me."

Appearing on the show has always been a nerve-racking experience. Guests have often struggled to strike the right balance between being serious and funny. Political aides would insist on briefing their bosses at length to try to prevent any missteps. It did not always work out. Asked once to name his worst guest, Stewart answered without having to think very hard: Sen. Harry Reid of Nevada, the Democratic leader. "He was like in a coma," Stewart said.

Though Stewart is often characterized by the conservative news media as a liberal, he has reserved some of his most damaging commentary for Democrats. When the Obama administration sought to do damage control in 2013 as its HealthCare.gov website kept failing, it agreed to allow Stewart to interview Kathleen Sebelius, then the health and human services secretary.

Far from being the administration’s friendly softball pitcher, he ended up mocking the mismanagement of the Affordable Care Act in one of his more memorable and devastating interviews. He opened a laptop and asked her to sign up for coverage while he tried to download every movie ever made. "We’ll see which happens first," he said.

It was not the first time the Obama administration had recognized Stewart’s reach. President Barack Obama has done the show twice as president.

Sen. Tim Kaine, D-Va., who was a guest when he ran the Democratic National Committee, identified another aspect of "The Daily Show" that politicians appreciate: its subtle seriousness.

Even as he cracked jokes, Kaine said, "ultimately he was making a serious point. And sometimes it’s easier for people to grab serious points if it’s wrapped in a little bit of humor." Kaine also said that politicians didn’t mind, too much, the egos deflated along the way. "He punctured our tendencies to take ourselves too seriously."

Shepard Smith, the Fox News anchor, said he marveled at the way Stewart had elevated the Arab Spring to a story that younger audiences could appreciate and understand. "He taught them why they should care," Smith said.

Fox News has been another favorite target of Stewart’s. Smith recalled the time Stewart went after his new set, which is as large as a trading floor and has gigantic touch-screen displays the size of small cars.

"He said that it looked the Apple Genius Bar had had an orgasm," Smith said with a laugh.

Coincidentally, the two men lived in the same apartment building in Greenwich Village. Right after the Sept. 11 attacks, Smith said he remembered Stewart describing the view of ground zero that he could see from their roof. It stuck with him for its poignancy and drove home how Stewart was always much more than a comedian.

The World Trade Center, before the attacks, had always obscured the Statue of Liberty, Smith said.

"One of his observations was," Smith went on, describing Stewart’s monologue, "‘We can see Lady Liberty where we couldn’t before. There’s a smoldering heap in the middle of the view, but that’s going to go away, and freedom lives.’ That meant a lot to me."