Yes, the whackjobs are already out in force. Google is your friend if you're looking for discussions of whether or not US president Barack Obama had Supreme Court justice Antonin Scalia killed, so that Obama would be able to appoint one more justice before leaving office.
But if we're going to throw around unlikely conspiracy theories, let's take it from both directions. If Scalia was murdered, why assume that the Democrats are the culprits?
Maybe Mitch McConnell and some Republican National Committee people got together and said "what better way to promote our presidential prospects than making the election all about the future of the Supreme Court? Let's create a vacancy, goad Obama into appointing someone we can attack as 'too liberal,' and turn the presidential election into a referendum on that instead of on our really ugly presidential nominee versus their really ugly presidential nominee."
Just sayin' ...