US and UK were not ready to open a second front tin Europe which Stalin ignored during the World war.
Explanation:
US and UK were not willing to open a second front in the war from the eastern side due to the neutrality of most of the countries from that side and the imminent disturbance it would create looking back at the destruction at the second front in the first war.
Russia itself had faced massive casualties on the front in the first war but were seeming more confident of the win for this time so they took the call of going in despite lack of support.
