It would be a delicious irony if Francine Busby’s defeat last June turned out to model Democratic victories in November.

After Busby’s loss, Republicans proclaimed Democrats’ hopes for 2006 dead. RCCC Chair Tom Reynolds urged “National Democrats [to] come to terms with the fact that momentum for the midterm elections will not materialize simply because they preordain it...”

Press and pundits joined in the eulogies. “Bilbray Punctures Democrats’ Plans To Retake House” opined the headline in the San Diego Union Tribune. The Washington Post headline noted that “Victory in California Calms GOP.” The Hotline synthesized the coverage this way: “The CA 50 special runoff left GOPers with ‘control of the seat’ while offering ‘scant evidence’ of a ‘highly energized’ Dem electorate that analysts say ‘would be necessary to dislodge the GOP from power.’ The ‘results settled GOP nerves.’”

Some urged a deeper look at the results, but they were hustled off the stage. California 50 is an extraordinarily Republican District, yet holding the seat required the GOP to spend upwards of $5 million dollars.

While Busby did lose to Republican Brian Bilbray, she gained eight points over her performance two years before. What if the eight-point swing in California’s 50th District portends a nationwide eight-point shift toward Democrats? Let’s do some arithmetic.

In 2004, 46.5 percent of voters cast ballots for Democrats in House races nationwide. An eight-point swing would mean 54.5 percent of the national Congressional vote for the Democrats this year, yielding a nine-point margin over Republicans.

The three most recent national polls give Democrats an average lead of 16 points in the generic Congressional vote. That is the widest margin in the generic vote for either party since 1974, when a 20-point advantage in the generic led to a 49-seat Democratic gain. Of course, history suggests the generic vote overstates the actual vote for Democratic House candidates on Election Day.  Professor Charles Franklin estimates that a generic advantage of about 16 points translates into 53 percent of the actual vote for Democrats, tantalizingly close to the margin produced by the “Busby shift.”

Translating those vote swings into actual seats won is another matter. Incumbency advantages, partisan polarization, redistricting and other factors have made the division of House seats much less responsive to the prevailing political mood than it was in earlier decades. It is harder for Democrats to win seats than to win votes.  That structural stability (discussed previously in this column) creates a situation like 1996 where Democrats can win a plurality of the national House vote and still only end up with 206 House seats.

But let’s do a thought experiment and assume the eight-point “Busby surge” is distributed evenly across the country. The result: Republicans would lose 37 seats.

Of course, it is unlikely such a shift would be spread equally across the country. More commonly it is greater in some districts, less in others, creating the potential for greater or lesser losses. Sophisticated academic models, which attempt to account for some of the other influences, suggest Democratic gains ranging from 12 to 29 seats, with most in the 22- to 29-seat range. Again, the “Busby model” appears to serve as a useful trope.

In the end, of course, there is no particular reason that the results of one California special election in June should foreshadow the national results in November — though it would have been hard to discern that from the coverage at the time. And much of the above is more a game than a prediction. But the speculation should be enough to bring smiles to the faces of those who worked so hard and felt so frustrated last June.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982, including Sen. John Kerry (D-Mass.) in 2004.