The argument they'll most likely make is that the merger will encourage competition by allowing them to compete with Netflix, Amazon, etc. in an evolving landscape that they're trying to keep up with (i.e. "if you don't let us do this, those guys are going to take over the world"). Similar arguments have been made for the AT&T/Time Warner merger and we'll see if it carries any weight when they face of with the DOJ in March. Not a perfect proxy given that one is horizontal and the other vertical, but may be a helpful indicator nonetheless.
