If I were Juneau, I'd wait until the seat opens up in 2018 when Zinke tries to take down Tester. Tester's campaign would bolster her numbers substantially, and I think she could win an open seat.
Midterms.. They are almost invariably bad for Democrats now, as their base becomes more and more minority-oriented....
May not be the case if there's a incumbent Republican president in 2018; however, I suspect in such a scenario Zinke would prefer to stay in the House and not challenge Tester. Zinke could still go down to Juneau if 2018 turns-out to be a pretty hostile environment for the GOP.
