The Washington Post‘s Chris Cillizza is reporting that Massachusetts Democrats are having a hard time trying to find someone who will run against Sen. Scott Brown (R-MA) in 2012. Two of the likeliest candidates, Congressmen Mike Capuano and Stephen Lynch, have been awfully quiet. Boston Mayor Tom Menino has flatly declared Brown unbeatable.

It’s certainly an odd situation. National Democrats haven’t been shy about suggesting that Brown is their top target next year. Last month Brown came under heavy fire from Tea Party groups, both inside in Massachusetts and outside. Certainly, whenever I write about Brown I find that most commenters here are very critical of him. But could he still be too popular with independents in the Bay State?

As I’ve often pointed out, Brown — like the Republican House majority — won by appealing to two groups: conservatives inside and outside of Massachusetts who wanted a 41st vote against Obama and independents who wanted someone to break one-party rule in Washington. He has tried to maintain his appeal to both groups, but in the process his votes have the potential to make both sides angry at times. The big question is whether the anger at Brown is more intense outside of Massachusetts than it is within the commonwealth, making Brown a tough incumbent to knock off — and making the 2010 gubernatorial election look like even more of a missed opportunity for the Republicans.