One of the mightiest warships of the U.S. Navy was also ironically the least useful. The USS Alaska and her sister ship USS Guam were the largest cruisers constructed by U.S. shipyards during World War II, ironically to counter a threat that never materialized. Although fast and powerful in their own right, the ships were rendered obsolete as offensive weapons by naval airpower and served out the war as escorts for aircraft carriers. The cruiser warship was conceived in the nineteenth century, as the advent of steam powder, shells, and other naval innovations reshaped seapower. The cruiser was conceived as a fast, heavily armed, but relatively lightly armored ship that could take on smaller groups of destroyers, protect civilian merchant ships, and carry out scouting missions. The cruiser was a ship that provided an important “economy of force” option that allowed naval commanders to detach them for missions that didn’t quite rate a battleship’s attention.