In 1945 he was assigned to General Douglas MacArthur's SCAP staff in occupied Japan (Book Notes 1978:836), where he played a major role in developing and introducing the land reform program that dismantled a power structure dominated by wealthy landlords.

In December 1954, during the period of McCarthyism in the United States, Ladejinsky was the central figure in a highly public incident which aroused furor among liberals in Congress and was resolved by the intervention of the White House (Schrecker 1998:293–94).

Members of the press repeatedly questioned President Eisenhower regarding the Ladejinsky case at a news conference held on January 12, 1955, particularly focusing on the fact that Ladejinsky was almost immediately chosen by Harold Stassen at the Foreign Operations Administration to direct the land reform program in South Vietnam, giving him full security clearance in order to fill a position even more sensitive than his previous one (Schrecker 1998:293; Back To Work 1955).

One quoted Benson as having "branded Ladejinsky flatly as a member of two Communist front organizations, and as an economist analyst, and investigator for Amtorg, the Russian trading agency" (Woolley & Peters 2007b).

Author James Michener wrote a letter to the New York Times stating "It is precisely as if Richard Nixon and Adlai Stevenson were to be charged with subversion.