President truman opted not to run for reelection for a second time primarily because

A) the national focus shifted from domestic affairs to foreign policy concerns.

Explanation:

Harry S. Truman was the president of the United States of America from 1945 to 1953. Though his attention to the foreign policy which involves the nuclear bombing on Japan, declaring the United States cause for the Korean War, etc gained him huge prestige. Though blow came from his proposed reforms in domestic policies which included increasing wages, full employment, decreasing prices and coordination between trad union and corporations.