The NY Times on a Progressives' challenge in Nebraska:
For all the talk of an angry conservative electorate this year, those on the left side of the spectrum are plenty angry, too, frustrated that President Obama and the majorities his party enjoys in Congress have not accomplished more to enact a liberal agenda. And the primary in Arkansas, one of the most conservative of Democratic bastions, has become a place for liberals to vent frustrations and invest millions for television ads to unseat an incumbent.
And the Times on Kentucky's Tea Party challenge to the GOP:
In Kentucky, the Tea Party movement, with the voter discontent it has captured, has found its purest standard bearer in Rand Paul, who is challenging Mr. Grayson for the Republican nomination. An ophthalmologist, Dr. Paul is the son of Representative Ron Paul of Texas, the 2008 Republican presidential candidate whose libertarian backers often take credit for being the germ of the Tea Party.
While there are candidates backed by the Tea Party in other states, none is so much a product of it, with the name recognition and the fund-raising prowess (through his father’s network). And the proportions of Kentucky’s voter registration make it impossible for any Republican to win a general election without Democratic support, so if Dr. Paul wins the primary on May 18, as polls suggest he will, the Tea Party will have to prove its appeal beyond the Republican right.
It's going to make for a very interesting Primary season.