Absent a congressional declaration of war  

The 1st Circuit should have a ruling on presidential war powers in the next couple days, according to this WP story. Courts dismissed a similar case in 91, but apparently this case has more merit since Congress has (some would say prematurely) passed a resolution authorizing a war. This is what interests me most:

The plaintiffs in this case argue that the constitutional founders wanted to forestall a monarchical executive who might squander the treasury and thousands of young lives on war. By giving Congress the right to declare war, the plaintiffs argue, the Founding Fathers situated war-making powers in the most representative wing of government.

I had always thought of this as a separation of powers issue, but it makes sense to vest the power to declare war with the most representative branch of government. I don't have any illusions that Bush would fail to get a declaration, but in a time of rapidly expanding executive power, this is attractive. Given our new strategy of deficit-funded preemption, the stuff about a monarchical executive squandering the treasury seems awfully relevant.