Some conservatives view this as a sellout on the part of Brown. I don't necessarily think that is the case. Brown's only responsibilities are to the Massachusetts people; if he believes a piece of legislation is something they'd support, he should be under no obligation to conservatives or "tea-party-nistas". Now if we could only wrangle up Lincoln Chafee to come back to the Senate and we would be set!
I think bipartisan legislation can only be accomplished through moderates who are willing to cross party lines for something they believe in. People like Mitch McConnell and Harry Reid may make a lot of noise and show, but in the end, it is in the hands of moderates that true groundbreaking legislation rests.