It was the first of America's politically waged wars. The only one that was successful to a degree, was Gulf One, but that was left unfinished because of political considerations which allowed the formation of the Coalition.
The Gulf of Tonkin Resolution gave Johnson complete authority to conduct the war as he saw fit from the White House (no congressional approval). At the time that Congress authorized it, the public was completely behind it.
It was the first TV war coming into American homes every nite. The media, the politicians, the military and the voters all had their opinions about the war and the country fractured into turmoil, which still resonates today!