Too early!
I don't see her not running for re-election, but if that's the premise, then it really depends on how popular she is when leaving and what shape the country is in. As well as when she announces, or else the Democrats will have a serious fundraising/organizational disadvantage.
O'Malley would probably want it. So would Cuomo. Gillibrand would probably be a popular choice (and she'll have gotten to replace Clinton twice!
).
But hopefully it's a new Hispanic or Gay national star... so we could have another historic election.
