The Republicans have more or less already announced that they will refuse to consent to a replacement this term. That could change if Hillary wins (she will likely take the Senate with her if she does), but, the odds-on outcome is: Obama nominates someone, but no Obama nomination is confirmed.
It's not just that it's an election year, but that it's a closely divided Senate with a liberal President replacing the most reliable and influential conservative on the Court.
They're obviously going to say that now (keep in mind so far the people who've said that are Cruz who is on judiciary but will never approve any Dem candidate and McConnell who doesn't matter.)
The ones who matter most are probably Flake and Tillis since they're the least conservative among the judiciary members not up for reelection.
I think we'll see an initial stall for sure, and then in a few months it will depend on how polls are going, both in the senate and national races. Hillary + dem senate is the nightmare scenario for republicans, so they're likely to make a deal if that's still a strong possibility in July.
I agree that the 2016 election becoming a foregone conclusion is a circumstance in which a nomination might happen, but it's the only one. Equally importantly, by the time the election becomes reasonably predictable, Obama will be butting up against the limits of the window in which he can get a nomination through even in favorable conditions.
Obama will not replace Scalia. I like the Dem's chances this cycle and so am not despondent about this.
It's not just that it's an election year, but that it's a closely divided Senate with a liberal President replacing the most reliable and influential conservative on the Court.