It's called checks and balance.
Congress simply cannot dictate to the president that he should ignore a threat to the country and allow the country to be attacked.
This isn't 1776 where the big threat was wooden ships sailing into a harbor and begin lobing cannon balls into a city.
A country a half a world away can destroy cities with the push of a button.
A hand full of members of congress do not have the authority to say we are going to allow a city to be nuked and the president can't stop it.
Iran doesn’t have a nuke, and if they did they couldn’t launch it here anyway. Russia and China have ICBMs armed with nukes. Why aren’t you screaming for zero to attack them? N. Korea has nukes, how come we haven’t zotted them willy nilly?
The point here, is that if we believe that Iran is a threat we have ample time to a public debate and a declaration of war. Was Libya a threat? How about Vietnam? Korea? Bosnia? Kosovo? Now we are sending Special Forces troops to africa to help round up some thugs. Where is the threat there? Where does it end? The list just keeps getting longer and longer. When are you imperial presidency types gonna get tired of it all?