How did the vaunted Romney Death Star break down?

That was an understatement. Team Romney not only dropped oppo research on Gingrich; before it was all over, Romney and his SuperPAC allies spent about $15 million on ads in Florida, three times what Gingrich and his supporters spent. And all — literally all — of it was on negative advertising. “The only positive Romney ad aired over the past week was single Spanish-language radio ad,” ABC’s Jonathan Karl reported when it was over. Romney’s assault completely dominated the airwaves; 68 percent of all ads aired in Florida were Romney attacks on Gingrich. It worked; Romney won Florida handily. …

Now, the general election campaign is here, and the talk is of the Obama killing machine, not the Romney death star. By most accounts, the Romney campaign is not displaying the super-aggressive effectiveness it showed in the primaries. Why? Here are five factors:

1) The facts. Romney’s business history and taxes are two issues left unresolved from the primary campaign. During the primaries, Republicans didn’t want to hear fellow Republicans criticizing Romney’s record at Bain Capital. Some characterized attacks on Romney’s Bain history as attacks on capitalism itself. Democrats and many independents don’t feel the same way, and Obama and his SuperPAC allies are relentlessly slamming Romney’s business history both nationally and in key states around the country. Likewise, while most Republicans were satisfied with Romney’s release of one year’s tax returns, and promise to release one more, that minimalist offering has met less success in the general election fight.