According to Jane's Battleships of the 20th Century, the Alaskas were 'large cruisers' but possessed capabilities that put them far beyond the later 17,000-ton heavy cruisers of the Des Moines class. Their 12-inch armament and their length (only the Iowas were longer) naturally put them in the battle-cruiser bracket, even though calling them battle-cruisers was officially discouraged.
In some ways the Alaskas can be seen as the ultimate US heavy cruiser, taking existing trends in heavy cruiser design to their logical extreme. They were superior to any known cruiser but deficient in respect to any known battleship. Although capable of their 33 knots, this gave no margin over the Iowas which were already entering service at the same time. Primarily, they were designed to be cruiser killers, and later, Fleet Admiral Ernest King championed them as potential close escorts for the fast carriers.