Well that completes the set of all Dem senators in states that voted for Obama in 2012 (aka the Blue States).
So the question is, who is next: a Red State Dem or another Blue State Pub?
I'm betting Murkowski, then Collins, then Landrieu.
Collins I'm assuming is worried about a primary challenge. Murkowski's "evolution" should be done in a year or so. Landrieu I can see pulling a Tim Johnson and holding back so it doesn't hurt her brother's campaign (if he even runs for Gov/Sen), though she strongly implied that she supports it already. A few months after her/her brother's campaign ends, expect an endorsement from her.
So the question is, who is next: a Red State Dem or another Blue State Pub?
I'm gonna say the next Pubs will be Murkowski, Susan Collins, maybe Toomey, Lindsey Graham once he comes out, maybe Mike Lee and maybe one of the Wyoming/Idaho Senators
What about Donnelly? Isn't he more like Baucus than Pryor?