The front-page story in the March 18th New York Times seemed a case of political life imitating art. A revival of The Best Man—Gore Vidal’s 1960 ode to the drama of a brokered convention—was in previews on Broadway. And there above the fold in the Sunday Times, Jeff Zeleny and Jim Rutenberg were reporting that suddenly political insiders were contemplating the serious possibility that front-runner Mitt Romney would arrive at the Tampa Convention short of the 1,144 delegates needed for nomination. The Times even used in its subhead the catnip-for-reporters phrase, “Open Convention.”

Just eight days later, the curtain slammed down on these second-ballot fantasies. Reflecting the new campaign-trail orthodoxy, Politico ran a major story Monday by Jonathan Martin saying, in effect, “It’s all over now, Baby Blue.” Martin portrayed Newt Gingrich and Rick Santorum as anti-Romney “hecklers, rather than competitors, with little money to even air cable-TV ads, increasingly far-fetched scenarios for going to Tampa and shrill rhetoric.” For The Washington Post on Tuesday, Chris Cillizza wrote an online piece with this the-end-is-nigh opening sentence, “The Republican primary race has reached—or, at the very least is well on its way to reaching—its conclusion.” About all that was missing was the ritual playing of “Taps.”

The verdict seems fitting for Gingrich, whose political epitaph I wrote for The New Republic after he finished a weak third in Saturday’s Louisiana primary. But what has happened to Santorum since March 18th to consign him to oblivion? How can he be fighting his way to Tampa one day and yesterday’s man the next?

There were no dramatic reversals in the mid-March voting. Only the terminally naive should have been surprised by the results of the Illinois and Louisiana primaries. Romney won Illinois (where only 29 percent of GOP voters call themselves “very conservative”) by a comfortable double-digit margin. But Santorum came roaring back in Louisiana (49 percent “very conservative”) with a 22-point landslide. If the back-to-back primaries changed anything, they stripped Gingrich of his last fragile claim to be the real conservative alternative to Romney. So, in theory, Santorum is finally set up with an unobstructed shot at Romney.

The only problem is that the cable networks and much of the political press corps seems determined to start pulling out the tent pegs while Santorum is still performing under the Big Top. Without new characters or visual effects more dramatic than close-ups of Etch-a-Sketch screens, television has finally grown bored with the inter-Mitt-able GOP race. As Howard Kurtz reported in The Daily Beast, “At the cable news networks…the word is out that the presidential campaign is sending the ratings south.” Belated endorsements like Jeb Bush going for Romney nearly two months after the Florida primary do not have much relevance to the voters, but they do send a message to sophisticated reporters that the fix is in.

The day after Romney won Illinois and Puerto Rico (not exactly a political bellwether), New York Times polling guru Nate Silver wrote an online piece entitled, “G.O.P. Nomination Becoming a One-Man Race.” Taking as gospel the Associated Press delegate count (more about that later), Silver declared, “We’re getting close to the point where it might take a major revelation for Mr. Romney to lose.” Rather than brandishing the innards of polling data and concocting new political projection models, Silver mostly based his argument on indicators like the betting site Intrade (which gave Santorum a 1.5 percent chance of victory in Tampa) and conventional wisdom assumptions (“Nor does Mr. Santorum appear to possess the ability to control the media narrative”).

The problem with such glib media pronouncements is that Republican voters perversely think that their primary choices still matter. In Illinois, according to the exit polls, two thirds of the Republican voters said it was more important that their favored candidate prevail than the GOP race end soon. Despite the air of finality in the media coverage after Illinois, 70 percent of Louisiana Republicans preferred victory for their chosen candidate to a premature conclusion to the GOP primaries. It is a safe bet that Republicans in such major primary states as New York (April 24), Pennsylvania (ditto), Texas (May 29) and California (June 5) are not looking forward to being effectively disenfranchised by the time they vote.

So why are campaign reporters suddenly so eager to anoint Romney and devote more than four months to (be still my beating heart) non-stop vice-presidential speculation? Campaigning in Wisconsin Saturday, Santorum offered his own theory to supporters as he referred to his traveling press corps: “They’re all trying to go home, get off the road and stop writing about this thing. They’re all tired.”

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