FILE – This May 19, 2015 file photo shows the U.S. Navy amphibious assault ship USS Essex off the coast of Bellows Air Force Station, Hawaii during amphibious exercises. The U.S. Pacific Fleet is smaller than it was in the 1990s, helping fuel a debate about whether the U.S. has enough ships to meet challenges posed by fast-growing and increasingly assertive Chinese naval forces. (AP Photo/Caleb Jones, File)