[MitchellC]

I expect, however, there will be enormous pressure on all Senate Dem incumbents to stay put in 2014

That would go against the Dem strategy of the past two elections, wouldn't it? The Dems know it's often easier to win with a blank slate that can promise anything than it is to defend an incumbent who has ruined his reputation by actually voting like a Democrat.

[fieldmarshaldj]

Sometimes it works, sometimes it doesn’t. Ultimately, had the incumbents run, it may not have turned out any different.