The Whole World In Your Hands

Why not? They have nearly infinite soldiers ready for war. They will help for half of Russia. You agreed with them. With Russia busy with the Chinese, Germany invaded Britain. Soon Moscow is surrounded by the enemy. They knew they lost so they surrendured. Most countries surrendered to you except the Chinese. Luckily you bought hundreds of nuclear missiles during the war. The Chinese quickly surrendered to you. You are now Supreme Ruler of the Universe.