Naturally the republicans will try to delay this until the election. There's the obvious reason of wanting a republican in, but there is also the potential, for both parties, to use this to their advantage in election. If for example, Cruz proclaimed he would appoint a justice that would overturn Obergefell v. Hodges (gay marriage case), then he'll instantly get a large bump in the polls... cause people are concerned about that for some reason.
Of course, it doesn't matter if he actually can or would do that, but it gives credibility to the threat.
Hopefully, whoever is voted in stands against the Citizens United decision, which is by far the worst decision the court has made in many years.







