By Michael D. Shear, The Caucus @ nytimes.com,  April 15, 2011

In a city where almost everything seems up for debate these days, Republicans and Democrats in Washington agree on one thing: conservative groups, working outside the normal party structure, outperformed, outhustled and — most of all — outraised Democrats in 2010.

Led by Karl Rove, a former adviser to President George W. Bush, and, separately, the Koch brothers, two wealthy conservative financiers, the groups funneled tens of millions of dollars into ads that swamped Democrats and helped Republican candidates win election and capture control of the House.

Things may be changing.

Faced with the prospect of their candidates once again having to contend with a barrage of negative campaign ads financed by the Republican-leaning groups, Democrats are moving rapidly to join the party by creating groups of their own.....