What role would the Montana class have filled?

If the Montana-class battleships had been built, what role would they have served beside carriers?

They would form the heavy battle line, replacing the older standards and releasing faster Iowas for screening and pursuit missions.

Montana answered the prewar requirement for a heavily armed main battle line. Its speed was closer to that of the North Carolina and South Dakota classes than to the Iowas. Replacing older Standard-type battleships in the heavy line would free the faster Iowas to screen other capital units and pursue fast enemy ships. The proposed division of labor depended on the battle-line role that existed before the Second World War and had declined by its end.