The Republicans clearly do not have to confirm an Obama nominee and it would be nuts for them to do so. The Supreme Court is never a big voting issue - especially with the Democrats - and there is really very little in it for the GOP. Your going to hear a lot of arguments from the left about how the republicans really risk a lot by not confirming someone -- just like they did with immigration reform where they tried to sell the nonsense that the republicans had to cave because they could never win again with out the Hispanic vote. the country isn't going to care that there are 8 on the supreme court and that 4-4 ties go with the lower court decision and lack precedental value. It just isn't.
on the other hand approving ANY Obama nominee means TRump is the presidential nominee. Game over.
No one is suggesting they approve "ANY" Obama nominee. Many are finding fault with the Republicans who are saying they
won't approve any Obama nominee.
They are basically gambling with the Supreme Court to get a conservative to replace Scalia. They could work with Obama now on a replacement and get a moderate, just as Democrats did with Reagan in 1988 to confirm Kennedy. But that's not good enough for them. They are going for all or nothing. They are banking on winning the presidency and the Senate so they can install a conservative.
It could work out that way for them.
Or it could back fire on them and Democrats could win the presidency and the Senate and install a Liberal, making the court 5-3 Liberal with 1 swing vote.
That's all well and good but the issue isn't really a "moderate" either. Lets say that the Democrats served up another Kennedy in every respect who you feel is a moderate (and trust me to Barrack Obama he is no moderate -- Sonia Sotomaior is). That would change the current balance on the court. Maybe not as much as another Sotomaior would but it definitely would. It is the current balance that Obama wants to change and the Republicans are defending and have every political reason to do so. The reality that a "moderate" who would be appointed by Obama would just be a liberal judge who does not have much of a track record to shoot at.
And approving an Obama nominee hands the nomination to Trump (perhaps unfairly to Cruz and the others, but it does ) and they still are hoping they can stop him
And Obama would never take up your suggestion in the first place. Hes looking to turn the court left for generations and insure that his so called legacy doesn't get wrecked in the court which another Kennedy might do. He would clearly make the calculus that if the choice were a new Kennedy or taking his chances on the next election he would clearly take his chances on the next election s well. There is nothing in it for him to pick a moderate like Kennedy.
What this does illustrate is how absurd it is that in this democracy such important questions depend on who happens to die when whoever is in office. This shouldn't be such a crap shoot