Julia Roberts as a guest finally put Dave over the top in late night Tuesday night in the early Nielsen overnights following Howard Stern Monday night. They bested Conan and his guests of David Duchovny Monday night and Eddie Murphy on Tuesday night. And Eddie rarely does talk shows anymore so that was considered a guest “get” even if his movies bomb at the box office. True, Julia can’t open a movie anymore either, but she turned the tables on Dave last night and started interviewing him about his recent marriage, which Howard did as well.) It’s the nightmare scenario for GE/NBC Universal that everyone but boss Jeff Zucker thought would happen: the network’s cash cow The Tonight Show, once safely No. 1 in the ratings with Jay Leno as host, now can only hope to seesaw in the ratings with Letterman’s Late Show. And it’s all Zucker’s fault. You’d think that NBC would be in a flopsweat over O’Brien’s ratings slide during his first and second week as host of The Tonight Show. You’d think that, but you’d be wrong. Now, most network suits would be spending every minute of every hour of every day brainstorming how to make the show more popular. But this is NBC where, when the going gets rough, the executives go golfing. That’s right, Conan’s longtime executive producer Jeff Ross is getting his money’s worth out of his spankin’ new membership at Riviera Country Club because he was on the golf course not only two weekends in a row — but both Saturday and Sunday last weekend even after Conan’s ratings began to fall.

June 9th
David Letterman  3.4
Conan O’Brien  2.9

June 8th
David Letterman 3.0
Conan O’Brien 3.1

This follows the plunging of Conan’s Tonight Show ratings from a debut high of 7.0 on June 1st (vs 2.8 for Dave’s Late Show), to 5.0 on June 2nd (vs 3.0), 4.2 on June 3rd (vs 2.8), 3.8 on June 4th (vs 3.2), to 3.5 on June 4th (vs 2.7).

Of course, helping Dave is the fact that, just last week, CBS had every one of the Nielsen Top 10 shows in network primetime in this period known as the summer repeat doldrums. And NBC’s primetime schedule is, as usual, tanking. (I told you that NBC even got bitch-slapped by Univision in the 8PM and 9PM hours.) So no help there for Conan.

There’s more bad news: Advertising Age reported Monday that while “NBC is touting Jay Leno’s new primentime program as an innovative, DVR-proof move, buyers say the new talk show will draw fewer viewers than ABC and CBS on any given night, and are balking at paying primetime prices for what they view ads late-night ratings. ‘He will guarantee NBC a third-place finish [behind ABC and CBS] in whatever hour he’s in,’ said Shari Ann Brill, senior VP-director of strategic audience analysis for Aegis gGroup’s Carat. ‘He will do on par with what he did in late night.’ ”

Sure, Zucker and his minions keep repeating the mantra that it doesn’t matter if Leno’s new show gets whipped in the ratings by scripted dramas because “we’re managing for margins, not ratings” because the programming not only will be cheaper to produce but also fresher throughout the year when other networks have to go into repeats. That argument isn’t cutting it with Madison Avenue. So what is Ben Silverman’s supposedly “creative” solution to appease advertisers who don’t want to pay primetime rates for late night ratings? He recently told Ad Age “the network would consider offering the opportunity to have Mr. Leno do live commercials, which he suggested would potentially be worth a price increase.”

Uh, did anyone at NBC even bother to tell Leno he may become a 10PM pitchman starting September 14th? A throwback holding up cans of Campbell Chunky Soup and bags of Purina Dog Chow while telling viewers how much he likes the products? How humiliating for Jay. He should have taken up ABC on that offer to compete with both Dave and Conan. Especially now that NBC executives have barraged Leno and his people with network edicts indicating the brass is favoring Cona’s show, like demands that Jay back off booking A-list celebrities because it would encroach on O’Brien’s turf.

One thing is certain: gone is Conan’s all-too-brief honeymoon period with the press. Not even NBCU’s PR War Room set up by Zucker will be able to spin this disaster. Because, while Conan’s debut was the highest-rated Monday episode of the veteran franchise in four years, June 5th’s was the lowest rated Friday episode in 6 months.

In the old days of network TV, a top executive who made such a horrendous mistake as Zucker did would not even wait to be fired: he’d have the class to offer his immediate resignation. But nothing seems to shame Jeff. Though many have tried. Just this past weekend, Marc Cherry reminded a packed audience at the “Produced By” Conference put on by the Producers Guild Of America about another error in judgment from the then NBC Entertainment President:

Cherry said that, after his Desperate Housewives became a huge hit for ABC in the fall of 2003, then NBCU chairman Bob Wright called and asked who at his network had passed on the show. Cherry told Wright that he’d given the pilot script to Karey Burke, then NBC’s EVP of primetime series development, and she’d loved it. But then Burke gave it to Jeff Zucker, who passed. ”The heat went onto Karey, who was soon looking for a new job,” Cherry said. “They were looking for someone else to blame.” And Zucker? That December, he was promoted to president of NBC’s Entertainment, News & Cable Group. And promoted again in 2004. And again in 2005. And promoted again in 2007 to his present job.

Editor-in-Chief Nikki Finke - tip her here.