Well I am no fan of tv and rarely turn it on and I understand why the writer's are striking, but why can't Leno write his own jokes. I must admit that seems stupid. A comedian should be able to write and deliver!

EW YORK (AP) -- Jay Leno kept the jokes coming his second night back on the air, even as the striking writers union and his network sparred over whether he was violating union rules by writing his monologues.

The Writers Guild of America had scolded the "Tonight Show" host earlier Thursday for penning and delivering punch lines in his first monologue in two months, aired on NBC the night before.

NBC quickly fired back, arguing Leno, a guild member, was right and the guild was wrong.

"The WGA agreement permits Jay Leno to write his own monologue for 'The Tonight Show,' " NBC said in a statement. "The WGA is not permitted to implement rules that conflict with the terms of the collective bargaining agreement between the studios and the WGA."

The agreement between the guild and producers expired October 31, but its terms remain in effect, said Andrea Hartman, executive vice president and deputy general counsel for NBC Universal. She cited federal labor law.

According to the contract, "material written by the person who delivers it on the air" is exempted from the agreement. The exception applies to shows outside prime-time, which includes NBC's "Tonight Show."

Leno did not mention the dispute during his show Thursday. Watch the hosts return to air »

For its part, the union argues that it's on firm ground in the context of either its "strike rules" or the expired contract.

"Our position is that our strike rules don't conflict here and, because he's (Leno) always been employed as a writer" on the show, the contract exception doesn't apply to him, guild spokesman Neal Sacharow said.

Sacharow declined comment on whether the guild would move against Leno. But he said any violation of strike rules would be brought before a union compliance committee for evaluation and a recommendation for action.

That could mean a fine or loss of union membership.

Leno is "busying himself with the show," his publicist, Dick Guttman, said Thursday when asked if the comedian had any comment.

The guild's upbraiding of Leno came despite his public support for the union, including delivering doughnuts to a picket line. Leno also paid his employees' salaries -- except for the writers -- while he was off the air, and "Tonight Show" writers were pointedly absent from a picket line outside his studio Wednesday.

Much of Leno's first monologue discussed the strike that had kept him absent, and he poked fun at NBC Universal boss Jeff Zucker's "mansion." But there were also standard monologue jokes about Paul McCartney's divorce, the weather in Iowa and Britney Spears.

Leno told viewers he wrote his own jokes and that he didn't turn to "outside guys."

"I'm doing what I did the day I started," he said. "I write jokes and wake my wife up in the middle of the night and say, 'Honey, is this funny?' So if this monologue doesn't work it's my wife's fault."

He maintained: "We are following the guild thing. We can write for ourselves."

Leno returned Wednesday, as did four other late-night hosts after having been off the air since the strike began November 5. He was seen by 7.2 million viewers, while CBS rival "Late Show with David Letterman" drew an audience of 5.5 million. Letterman's audience was 45 percent more than his pre-strike average this season; for Leno, it was a 43 percent bump and his biggest audience in two years, Nielsen Media Research said.

Letterman's Worldwide Pants production company reached an interim deal to bring staff writers back for both "Late Show" and "Late Late Show with Craig Ferguson," also on CBS.

Ferguson was seen by 2.2 million people, up 28 percent, but was edged out by NBC's "Late Night with Conan O'Brien" with 2.8 million viewers, up 37 percent from his pre-strike average, Nielsen said.

On ABC, "Jimmy Kimmel Live" had an audience of 1.8 million, slightly down from his season average