The Penisnsula is nearly cut off. Though, there are a few German units rushing up to fill the gap. At a minimum disrupt the operation to cut it off. If the next turn ended as is, the Germans would be cut off and the Allies would secure an Auto Victory! However, these are really strong units coming on.
Now the question becomes, do I attack the Amis that are sitting there or do I simply try to build up a line of units to keep supply open. I don't have the map in front of me to see if this is possible.