With regard to the level-of-service reviews that are happening in all the towers, that decision is ultimately with the Minister of Transport. He'll have the authority to either agree or not agree with the report, if it even makes it to his desk.
With regard to the service in the area control centres, that's a different situation. That's strictly regulated by Nav Canada. Of course, they have to provide the service, and if they're unable to provide the service, then obviously the minister would have to intervene as well. For the most part, though, staffing in area control centres is strictly Nav Canada; it's under their purview.