Judging from the lopsided tenor of most of the coverage during the broadcast day on Fox News on the Monday before the Wisconsin and Maryland primaries, Mitt Romney already had been anointed as the GOP nominee. In contrast, Rick Santorum was often as invisible as a purged Soviet general airbrushed out of history by Stalin. In fact, about the only time that Santorum regularly popped up on the Fox News screens was as the butt of an attack ad (“Rick Santorum: Big Spender, Washington Insider”) sponsored by the pro-Romney super PAC, Restore Our Future.

Although I normally disdain braggadocio, I am compelled to confess my expertise on the subject of Fox News: I (martyr alert) watched 10 hours of the network’s programming on Monday. Probably my only rivals for the couch-potato crown are a few Fox News producers and a handful of chair-bound conservatives who forgot to change the batteries in their remotes. My goal was not to research a predictable liberal screed mocking Fox’s portrayal of Barack Obama, although I did have to giggle when Sean Hannity ran a feature on the president with the onscreen headline, “SOCIALISM IN AMERICA.”

Instead, what fascinated me was what Fox News was telling Republicans about the presidential nomination fight within their own party. Fox would probably be the first stop for an undecided GOP primary voter still trying to get a handle on Romney and Santorum. A January poll by the Pew Research Center found that 36 percent of all Republicans and 53 percent of Tea Party supporters describe Fox News as their leading source of campaign news. As a result, it was tempting to conclude in advance of the voting that as Fox News goes, so goes Wisconsin and Maryland. And Fox News goes for Romney.

This latest eye-glaze marathon kicked off with two hours of Fox & Friends, beginning at 7:00 in the morning (all times Eastern). This is a show that I have occasionally appeared on in the past, so I was not surprised to get my full morning briefing on fringe groups like the New Black Panther Party and to be treated to an in-depth discussion of the allure of Donald Trump’s new fragrance, “Success” cologne. (Appearing on Fox & Friends from a secure remote location, Trump also peddled the discredited notion that autism is linked to vaccinations).

I can understand why the show’s producers were irresistibly attracted to a fun-never-stops Romney video of the candidate in Wisconsin being punked on April Fool’s Day by being led into an empty room for a speech. The on-screen Chyron for the Romney segment read, “A GOOD SPORT.” But during the two hours of the show most likely to be watched in Wisconsin (which is on Central Time), the only extended discussion of Santorum came courtesy of conservative firebrand Ann Coulter, a Romney supporter. Coulter appeared on set armed with poison-tipped talking points: “Rick Santorum is not the most conservative candidate in the race…. Rick Santorum voted six times to re-fund the National Endowment for the Arts…. This is not Ford versus Reagan; if anything, Romney is closer to Reagan.” Small wonder that host Steve Doocy said archly at the end of the segment, “She’s for Mitt Romney, can you tell?”

My point is not that Fox News should hype Santorum’s long-shot chances, but that the former Pennsylvania senator at least deserved to be treated like a real candidate on the cusp of a do-or-die primary. Of course, all losing candidates suffer the slings and arrows of dismissive punditry. Talking about Romney at the beginning of his 8:00 pm show, Bill O’Reilly said, “If the governor does win in Wisconsin, it’s pretty much all over. And the Republican Party can shift into beating President Obama.” An hour later, Fox News viewers heard Dick Morris, the former Bill Clinton pollster, tell Hannity, “Romney is going to win maybe eight primaries in a row, including Pennsylvania. Santorum can’t stay in the race after that.” Morris then hedged, saying that Santorum could, in theory, pointlessly continue after that.

But most of the time Santorum found himself on the eraser’s edge. Greta Van Susteren broadcast her 10:00 pm show, On the Record, from Milwaukee to better cover the primary. She began with a 15-minute taped Romney interview during which, to her credit, she asked the candidate about problems like poverty and failing schools rather than peppering him with predictable horse-race questions. Van Susteren’s other big “get” during the hour-long show was House Budget Committee Chairman Paul Ryan, who has, yes, endorsed Romney. Ryan warbled his on-message praise of the GOP front-runner: “I’m just convinced that he has the best conservative principles…and the best chance of beating Barack Obama.”

Walter Shapiro just chronicled his ninth presidential campaign. He writes the “Character Sketch” political column for Yahoo News. Follow him on Twitter @WalterShapiroPD.