Which event most contributed to the changing troop levels shown in this graph?
The Twenty-Sixth Amendment lowered the draft age to 18 from 21.
U.S. and North Vietnamese ships exchanged fire in the Gulf of Tonkin.
Congress expanded presidential powers to wage war under the War Powers Act.
Communist troops launched a series of attacks during the Tet Offensive.
The Twenty-Sixth Amendment lowered the draft age to 18 from 21.
U.S. and North Vietnamese ships exchanged fire in the Gulf of Tonkin.
Congress expanded presidential powers to wage war under the War Powers Act.
Communist troops launched a series of attacks during the Tet Offensive.