When President Theodore Roosevelt wanted to send the U.S. Grand Fleet on a global tour to show America's flag and might, he petitioned congress for money for the fuel that would be required. When Congress refused, Teddy said "Fine. I have enough fuel to send it half way around the world. I will leave it to congress to bring it home." Congress provided the fuel knowing that Mr. Roosevelt, as Commander-in-Chief, was within his authority.
Regardless of what decision President Obama makes concerning retaliation for Syria's use of gas in his civil war, it will be a mistake for him to seek permission from Congress to act. There has always been tension between our three branches of government as each tries to increase its power over the other. But, in their wisdom, the Founders embedded in the Constitution equal power between the branches. Congress was given most of the war powers - raising an army, maintaining a navy, punishing "offenses against the laws of nations", and the power to declare war. But, the president was given authority to command the military - his only military function.
Of course, if Congress believes the president is acting irresponsibly they can refuse to fund operations or they can impeach him. However, legislation such as the War Powers Resolution, of 1973, which demands a president notify Congress within 48 hours of starting hostilities and cease operations within 90 days unless Congressional authorization is received, has been ignored by every president as a violation of his authority - and rightly so.
Especially in these times of high technology, it would be dangerous to take away the ability of the president to act immediately in an emergency. President Obama, however reluctantly, is learning that the "buck" truly does stop with him. Any president should find it wise to seek advice from Congress when contemplating sending Americans into harm's way - but not the authority to do so. That's why we pay him the big bucks.