The Soviet Union challenged the legitimacy of the war for several reasons. The ROK Army intelligence upon which Resolution 83 was based came from U.S. Intelligence; North Korea was not invited as a sitting temporary member of the UN, which violated UN Charter Article 32; and the Korean conflict was beyond the UN Charter's scope, because the initial north–south border fighting was classed as a civil war. Because the Soviet Union was boycotting the Security Council at the time, legal scholars posited that deciding upon an action of this type required the unanimous vote of the five permanent members.

What country challenged the legitimacy of the Korean War?