Former pizza magnate Herman Cain’s upset victory in the September 24 Florida Republican straw poll, and his subsequent rise to a competitive third place position in at least one national poll, are being generally interpreted as a function of GOP voter unhappiness with previous “top-tier” candidates (Mitt Romney, Rick Perry, and arguably Michele Bachmann and Ron Paul). In particular, Rick Perry’s series of ever-deteriorating debate performances have apparently made more than a few conservative base voters restless, creating at least a temporary opening for the smooth and genial Cain, who has always been popular with the Tea Party crowd.

But something a bit more profound than happy feet (and the perpetual desire to refute “liberal media” claims of latent racism) may be driving Republicans in Cain’s direction. His relentless advocacy of a comprehensive overhaul of the federal tax code, bearing the catchy moniker of “9-9-9,” is getting serious attention in the conservative chattering classes. That’s happening for two pretty obvious reasons.

First, the increasing nastiness of the Romney-Perry competition, and perhaps even some fatigue with the entire field’s monotonous Obama-bashing, has created a natural desire for a more positive campaign focused on what Republicans propose rather than what they oppose. As conservative opinion-leader Erick Erickson argued after Cain’s Florida straw poll win:

They voted for Herman Cain because he is not running against Barack Obama so much as he is running for an America he believes in and that other people can get excited about. People love Herman Cain’s optimism. They love his vision. They love his 9-9-9 plan. The last is key. Herman has an articulated, easy to remember plan for economic recovery in his 9-9-9 plan. Quick! What is Mitt Romney’s plan? Jon Huntsman’s? Rick Perry’s? Michele Bachmann’s? They all, more or less, have them, but they are not readily memorable or easy to understand. Herman Cain is consistently conservative, he is running for something, not against someone, and he is the most optimistic candidate on stage.

Second, Republicans are sensitive to Democratic claims, amplified recently by Barack Obama’s attacks on Republican obstructionism, that their party has no real plan for reviving the economy. Obama’s consistent lead in the polls against all the Republican candidates (with the occasional exception of Mitt Romney) even as his approval ratings sink has to be alarming to conservative elites who are smart and honest enough to acknowledge that the president is beginning to succeed in his efforts to make 2012 a “comparative” rather than a “referendum” election. Hence, even for Republicans who don’t take Cain seriously as a viable presidential candidate, praising him for being a candidate of great substance with very specific plans for the economy is good for the cause.

The plan itself is a variation on the “Fair Tax” concept, which would replace existing payroll and income taxes with a flat national consumption tax. This hardy perennial of conservative tax schemes, which experts, even on the right, tend to deride as impractical and impossibly regressive, remains popular with the conservative rank-and-file. Cain has long been a Fair Tax fan, and frankly describes 9-9-9 as a way station to ultimate establishment of a Fair Tax.