There are a couple of differences between the two cases in Jones v Bush, that suit would have at most prevented Cheney from serving as vice president. In addition the electors of Texas would be the ones guilty of breaking the law. The problem in this case is that if Obama is not president of the United States he cannot give orders to the military and as a result if a member of the military follows those orders he will be guilty of following an illegal order.
That wasn't the point of ruling. The point of the ruling was that people filling the lawsuit had no standing because they were not candidates. Plain and simple as day.