1 Answer

You are correct, a declaration of war must be declared by the Congress, according to the Constitution .

However Obama is free to do as he wishes because several year ago, because of todays modern warfare where the country can be hit by missiles, the Congress passed the "War Powers Act," giving the President as Commander in Chief the authority to wage war on his own because complying to the restraints of the Constitution could put the county in jeopardy.  Under that Act the President is required to seek the power to continue to engage a war, within thirty days.

For example President Clinton was given the authority by the Congress to attack the source of the missile threats from Irag, against our our efforts to enforce "No fly Zones," over Irag, that were established as part of the cease fire ending the first Gulf war.

When Bush wanted to attack Irag for not complying with the cease fire agreement ending the first Gulf war, by failing to account for and destroy all of the "Weapons of Mass Destruction" that HE said he possessed,  Bush again went to the Congress to ask and he was given approval to attack Irag, without a Declaration of War.

Another thing many do not understand is the US Military, as well as the CIA, CAN NOT operate or take up arms within the country!

That was the reason only the US Cost Guard could assist within Louisiana after Hurricane Katrina. The various Governors MUST request the use of the US Military to take up arms. 

All of the Governors in the states effected by Hurricane Katrina requested help from the US Military days before Katrina made landfall.  The Governor of Louisiana did not ask for help until three days later when Bush informed her she needed to request the help of the US Military