Originally Posted by Dagoro
Edit: We have to take into account what Vergo said before Law and Smoker left him in the SAD room. He said that Law doesn't know everything about Dfla, that his connections run much deeper than Law realizes and replacing him will not be an easy task. Dfla might very well have something in his pocket that will unleash a shit storm upon Law.
Thinking back to the war when he was ordered to kill Moria, I can only conclude that either Kong or the Gorosei gave that order. Only they would have enough authority in the marines to do so. That could be the "connections" Vergo mentioned.
Though I could be wrong and the orders came from somebody outside the WG. If it was Kaido that gave the command, that would imply Moria might have been one of his allies or something which just doesn't seem right. Like wise the thought of DD working for Dragon and the revolutionary army doesn't quite seem legit either. There really aren't many other higher ups I can think up besides those.