Obama's U-turn on Social Security

At first, liberal groups played defense on chained CPI, accustomed to mobilizing in opposition rather than staking out a bolder claim. But the expansion movement can really be traced back to one blogger: Duncan Black, popularly known as “Atrios,” who waged an initially lonely crusade in a series of 2012 columns in USA Today, explaining why the retirement crisis was coming and how expanding Social Security represented the cleanest solution.

There are equally obvious solutions to other problems that Duncan Black won't see or accept for the same reason others didn't accept this one. Atrios and Social Security were a good fit, a problem that offered no personal conflict. And the timing was right.