First let me state (and I can say this as a fellow Sicilian-American) that Scalia will be regarded as one of the most acerbic, often mean-spirited, partisan in the modern Supreme Court.
But the question asked should be answered. Should Obama nominate to the Senate his choice to fill Scalia's seat? Bear in mind that there are still 11 months before a new president enters the oval office.
Regardless of the upcoming turbulent months, we should be mindful of the many changes that 2017 will usher to the political status quo: A new President......a new Senate makeup, and, of course, a much different Supreme Court in its ideological leanings.
Should Obama nominate to the Senate his choice to fill Scalia's seat?
I think the question is a bit fatuous. Of course he should, that is written in the Constitution and the president's obligation to nominate Supreme Court Justices. Therefore, it would be patently idiotic for him NOT to make a nomination.
However... that said, it is also in order for the Republicans to obstruct and block any nomination during a political campaign for the presidency. Again, it would be idiocy for them NOT to do this.
So the answer is, YES he should nominate someone and YES, the Republicans should block his nomination. I predict this is exactly what will unfold in the coming weeks and months. Partisans will make of this what they will, that is what is going to happen.
The Republicans control the Senate, therefore, they can utilize the filibuster to force a supermajority vote on confirmation, and this is what they SHOULD do. Justice Scalia was the only true Constitutional originalist on the court and there is no way a lame duck liberal president should get to pick his replacement... doesn't matter who he picks. If it were Ruth Bader Nutbag who croaked, it might be a different matter, but Scalia should be replaced by a similar Constitutionalist. Obama is never going to nominate someone like Scalia.
Now, people will protest that if Republicans try to obstruct, it will result in a backlash... I disagree... It will be a backlash if they DON'T try to obstruct in this case. The nature of our highest court should not be changed for the next 30 years on the basis of an untimely passing such as this. I would say, even in an off year, the Republicans would have an obligation to see that Scalia is replaced by someone with close to his views... which incidentally, once was the template for ALL justices to the Supreme Court. Someone who is going to abide by the letter of the Constitution's original intent without regard for left-right politics.
Republicans can do this without much effort because the confirmation process can be a very time consuming ordeal. Any nominee must first undergo a confirmation hearing... Republicans could drag that out for months and the more "moderate" the candidate Obama tries to go with, the longer they can mull over the choice. After months of hearings, they can simply reject the nominee and the whole process restarts with a new nominee. So I think this is what they will do. Run the clock, have the long protracted hearings, drag it out as long as possible, then reject the nominee without allowing a Senate vote. Start over, do the same thing again if necessary. Every time a Democrat cries "obstruction" simply point out how important this nomination is and the process must be followed, the nominee must be thoroughly vetted.
I mean... look, let's be honest here... no matter what Republicans do, Democrats aren't going to suddenly start liking Republicans. If they rubber stamped Obama's pick without much ado... the Democrats would chortle "suckers!" and politics as usual keeps marching on. So there is no winning over the hearts and minds of the liberal wackadoodles here. So you may as well go to the mat with this and reject whoever this yahoo nominates, stand your ground, don't back down. That said, I can already see the mealy-mouth GOPers laying the groundwork for approving an Obama pick if they're not "too liberal" because they don't want to confront this president.