Last I checked, presidents are elected for four years, not three. Which means President Obama should quickly nominate a replacement for Justice Antonin Scalia. Then the Senate should play its assigned role.
For the Senate to shut down the confirmation process would be bad for the court, bad for the country and, ultimately, bad for Republicans.
It would be bad for the court because it would leave a vacancy for more than a year, stretching across two terms and, in any number of important cases, preventing a majority from having a definitive say. (A four-four split affirms the lower court ruling and lacks value as precedent.)
It would be bad for the country for similar reasons. Citizens deserve conclusive answers on issues important enough to reach the high court, and divisive enough to split the justices, whether that involves Obama's executive actions on immigration, Texas' restrictive abortion law or the role of public-sector unions. They also deserve a functioning political process. Refusing to go forward would serve to deepen and entrench the existing partisanship and ensuing gridlock.
Finally, a Senate work stoppage would, actually, be bad for Republicans. In the capital these days, everything is political, every institution politicized. That may be inevitable and irreparable, yet tables here have a way of turning. One party's obstructionism ends up hurting it down the road.
Of course, a president in the final year of his second term, confronting a Senate controlled by the opposite party, is in a different position than one facing a high court vacancy earlier.
This reality appropriately shapes and constrains the president's choices about who can win confirmation. Throw in the filibuster, and it is clear how severely limited are Obama's options. Indeed, considering that any nominee must clear a 60-vote threshold, what is the risk Republicans perceive in following the regular order of holding hearings?
And as a pure matter of ideological calculation, might not conservatives be better off with what would have to be a consensus Obama nominee than gambling on winning the White House? What if instead they face a justice nominated by newly elected Hillary Clinton or Bernie Sanders, and a Senate controlled by Democrats?