Answer:
Vyacheslav Molotov, then-USSR's minister of foreign affairs, believed a second front should have been opened in 1942 to establish a balance against the Third Reich on North-West of Europe.
If the front is opened, Molotov predicted that the Nazi Germany would be stuck between USSR from the East of Europe and the Allies of the United States and the United Kingdom from the West.
If such a front is not opened, he feared that Hitler would order new offensives against the Soviet Union, which became truth on the summer of 1943.
Given that a second front in France was not opened until June 1944, the effect of that delay was negative on longer-term U.S.–Soviet relations. Although both sides then had worked together to defeat Fascism and restore order in the world, the disbelief eventually leaded to the Cold War.