blogs are by nature quick, impressionistic takes on issues. They can point you in the direction of deeper dives, but they will very rarely, I think, provide adequate evidence for policy decisions.

Case in point: Romney's tax plan. It would be ludicrous to trust a blog or an op-ed that threw some rough numbers together over the Tax Policy Center's results, as the latter are based on a well-established tax model built by non-partisan experts that has a long track record of generating reliable facts about tax policy. Certainly the blogs can play a very useful function in raising questions about the deeper studies, and even send the authors of the study back to the model for tweaks suggested by the bloggers.

But it's actually pretty shocking to me -- though I know I should develop a thicker skin -- that the Romney campaign is now lurching around, daily trotting out new "studies" and "solutions" to their math problem -- "we'll broaden the base (but can't say how)"... "we'll cap deductions at $17,000"... "whoops... that doesn't work... we'll cap them at $25,000."

[See here for TPC evidence that these caps also fail to raise enough revenue to offset the $5 trillion, 10-year cost of the tax cuts. Since most deductions and credits accrue to higher income households, the caps do, however, raise revenue in a progressive manner.]

The Romney team clearly threw out their tax plan -- 20 percent cuts across the board -- without any of the requisite spade work to see if it actually made sense. And now that real studies are challenging it, they're veering from "just trust us" to setting the evidentiary bar down so low that anything with numbers on it can clear it.