Obama's ISIS War Request Is an "Extraordinary Opportunity" for Congress
Try this thought experiment. Pretend that it's the spring of 1970. President Richard Nixon has just sent US troops into Cambodia. He thereby expands the Vietnam War, a costly undertaking already ongoing for years with no sign of victory in sight.
Now imagine further that Nixon sends a message to Congress asking that it authorize him to do what he has already done (while simultaneously insisting that even without legislative approval he already has the necessary authority).