It’s Why They’re Called Punch Lines : Comedy: Norm MacDonald is known for landing hard ones on ‘Saturday Night Live,’ with O.J. and Bob Dole among his favorite targets.

It’s not even dinner time, and already Norm MacDonald is talking commitment.

He’s talking fidelity and dedication and standing by your partner with a devotion Tammy Wynette would envy.

He’s talking about jokes.

Wedged into the corner table of a coffee shop near Manhattan’s Columbus Circle on a crisp December afternoon, “Saturday Night Live’s” lanky and laconic “Weekend Update” anchor is waxing philosophic about the relationship between the comedian and his or her best friend, the joke.

“If you don’t believe in the joke, why do it in the first place?” MacDonald asked in the understated manner in which he delivers some of his best punch lines. “Don’t let the audience be the judge of what’s funny. You either think it’s funny or you don’t. That’s the problem with comedy--it’s so subjective that you really can’t take other people’s opinions seriously.”

His philosophy appears to be paying off. From his cruelly funny impression of a cantankerous Sen. Bob Dole to his oft-disturbing takes on the latest news events as the “Weekend Update” anchor, MacDonald, 33, has won over the critics and pumped some life into the 20-year-old show’s otherwise hardened arteries.

Since “SNL’s” season opener in September, MacDonald has been getting laughs skewering O.J. Simpson and presidential candidate Dole almost every chance he gets.

In one “Update” report, MacDonald, using as a backdrop the infamous photo of Simpson defense attorney Johnnie Cochran trying on the ski hat his client was accused of wearing at the murder scene, quoted Simpson reprimanding Cochran: “Hey! Hey! Easy with that. That’s my lucky stabbing hat.”

He was just as brutal with Dole, mimicking the presidential candidate’s gruff delivery as well as his penchant to clutch pens, pencils or other writing implements with a near death-like grip in his right hand.

“I’ve always loved Bob Dole,” MacDonald said. “He’s like my favorite guy because I don’t know anything about politics, but I love guys who are characters. He tries his best to conceal his anger, but he’s not really cut out to be a politician.”

A former stand-up comic and writer for Dennis Miller’s short-lived 1992 syndicated talk show, MacDonald came to “SNL” in late 1993 after a stint writing on “Roseanne.”

At first, MacDonald wrote skits for other cast members, but he was soon writing and reading editorials for “Update,” then anchored by Kevin Nealon. By mid-1994, MacDonald replaced Nealon on “Update” as the comic actor wanted to focus more on sketches, MacDonald said.

If it’s intimidating sitting in the chair that launched Chevy Chase and Dennis Miller into the comedy big leagues, MacDonald doesn’t let it show. Dressed in blue jeans and a black leather jacket, MacDonald nursed his decaf coffee, lazily comparing the “Weekend Update” hosts who have gone before him.

Having worked for Miller, the anchor whose brutal cynicism seemed to define the 1980s, MacDonald said he learned from him the art of good joke writing. And he used to watch Chase when he was growing up in Quebec City.

“Chevy Chase was my favorite guy on the show because I always thought that he was funny without trying hard like all the rest of them,” MacDonald said.

Without trying. It’s a sentiment that could describe his own peculiar journey into the entertainment industry.

MacDonald’s stand-up career began on a whim one night back in 1987, when he and a bunch of friends just happened to drop by the Yuk Yuks comedy club in Ottawa. Although he had studied math and journalism at various times after high school, he was working then as a garbage collector.

“I didn’t know there were comedy clubs,” MacDonald recalled. “I didn’t think there were working comedians who did comedy. They just appeared on television, and as far as I knew there were only about six of them.”

The audience’s response to MacDonald’s impromptu shtick, however, was enough to get him started: “I thought it was the greatest thing,” he said.

But he certainly didn’t act like it, said Neil MacDonald, Norm’s older brother, a reporter for the Canadian Broadcasting Corp. Despite being a hit with the audience, Norm bolted from the club without telling the managers his name or phone number.

“They spent about two weeks tracking him down,” Neil said. “They found a friend who knew a friend who knew a friend who knew our mother and they called trying to find him.”

Norm MacDonald shrugged off the memory.

“I didn’t want it to get back to my family, just in case it didn’t work out. I mean, it’s not like it’s a real job,” MacDonald said. He paused, then laughed. “Actually, it’s a pretty weird job.”

Maybe so, but MacDonald has made it work. After doing Canada’s comedy club circuit for three years, he came to Los Angeles in 1990, pursuing stand-up work and then landing his writing gigs with Miller and Roseanne.

While “SNL” keeps him in New York for about 20 weeks of the year, MacDonald and his family--his wife, Connie, 32, and son, Dylan, 3--maintain a permanent residence in West Hollywood, the same two-bedroom apartment MacDonald rented when he first came to Los Angeles, just around the corner from the Improv comedy club.

MacDonald, who writes jokes and material almost every day, said he’s working on creating characters for himself to play on “SNL.” A voracious news hound, he’s constantly reading newspapers and watching TV newscasts to dig up more material for his weekly spot. A task that, of late, has not been too difficult.

“I’m probably the only guy who was happy Simpson was found innocent,” MacDonald deadpans. “Hey, whatever’s best for ‘Weekend Update.’ ”

* “Saturday Night Live” airs Saturdays at 11:30 p.m. on NBC (Channel 4).