(Bloomberg View) -- The Republican vow to significantly reduce the size of government is a foolish pipe dream, Larry Summers says, not because of liberal policy aspirations but because of structural economic realities.

At a lunch on Wednesday, Summers, a former Treasury secretary and a leading Democratic economic-policy thinker, explained the substantive as well as political impracticalities of cutting entitlements and defense spending in the years ahead.

"If we want to maintain traditional American values, government will need to be significantly larger," Summers declared at the event, hosted by the liberal Center on Budget and Policy Priorities.