would be a speech arguing for a military strike, but being pulled between a war-weary american public and his credibility and the u.s.'s credibility and instead became a speech to buy time. from the east room tuesday night president obama told americans why his administration is certain syrian president bashar al assad's regime is responsible for a sarin gas attack the u.s. government says killed more than 1,400 civilians. >> in the days leading up to august 21st, we know assad's chemical weapons personnel prepared for an attack near an area where they mix sarin gas. they distributed gas masks to their troops. then they fired rockets from a regime-controlled area into 11 neighborhoods that the regime has been trying to wipe clear of opposition forces. >> reporter: he made the case for a military response. >> this would be a targeted