What kept the Alaska class alive

When could the Alaska class have been cancelled, and what kept construction going?

The expected invasion of Japan and uncertainty about later Soviet heavy ships preserved plausible missions for the class.

Continued Alaska-class construction reflected uncertainty about how long and how destructively the Pacific War might continue. An invasion of Japan could have produced losses severe enough to justify every available heavy surface combatant. Postwar Soviet construction offered another possible mission, especially if Stalin pursued numerous large cruisers rather than a few battleships. American continuation of the Alaskas could then prompt a British equivalent because institutional acceptance of reduced naval status lagged behind Britain's economic decline.