I'd argue that the years since Kosovo have shown a desperate need for the Congress to regain control over the vital issue of war and peace. The Founders put it there for a reason. And yet we have turned the president into an emperor who can launch wars at a moment's notice and face little Congressional bowback.
And this is not an abstract question any more. Obama is now engaged in two illegal wars - in Libya and in Yemen.
There was no Congressional debate or vote on these wars - and one is being waged by the CIA with unmanned drones. I think we have learned a little about what happens when you give the CIA carte blanche to run a war with no accountability except to a president who has a vested interest in covering up errors.
And Boehner is correct that Obama owes us an explanation of his views on the power of the presidency. Can he declare war at will? Are these wars not-wars under his definition? What then qualifies as a war for Obama?
I couldn't tell you. What I can tell you is that many supported Obama to end wars - not to extend one, try not to quit another too quickly, and add two more for good measure. And Obama is a sophisticated and learned Constitutionalist. He must have thought about this question. What is his answer?
The administration has answered this, after a fashion, at least in the case of Libya. Short version: congressional approval is unnecessary because the US role is "limited" and the operation is under NATO command. This seems like pretty weak tea to me. I'm no expert on the War Powers Resolution, but I don't think that there is anything in it that makes the requirement to consult congress contingent on the particular command structure or scope of the operation.
The use of drones in Yemen is also troubling, if only because there may very well be no precedent or applicable statute governing the deployment of an entirely unmanned force. If so, this needs rectification sooner rather than later. The placement of American troops into harm's way is certainly the main reason war should approached judiciously and with checks on executive power, but it is not the only reason.