Was the Vietnam war an official war?

A declared war might have an official start; but not an un-declared war. The US Civil War was an un-declared war, but historians normally count the beginning of the "War of the Rebellion" when Fort Sumter was fired upon on April 12, 1861. Many historians count the Vietnam War starting in '61 when Kennedy sent in the Green Beret. But just as many historians count the beginning in '65 when Johnson sent in the Regulars. Some historians want to count the beginning when US Military men began dying in 1956.