Complex sentence: US President Matthews receives information from the British that the USSR will cease negotiations regarding grain and military concessions if the prisoners are released, so there appear to be only two potential outcomes: an ecological catastrophe, or a Soviet invasion of western Europe.
Split into simpler sentences: US president Matthews receives information from the British that the USSR will cease negotiations regarding grain and military concessions if the prisoners are released. So there appear to be only two options: an ecological catastrophe, or a Soviet invasion of western Europe.