Resolve or reach an agreement about (an argument or problem).
I believe the answer is: <span>war was fought on multiple fronts
The multiple fronts make the Allies surrounded from both sides which limit their movement/mobilization
The alliance have to face the millitary threat from Germany on the enters front. On this front, The soviet union played the most crucial role in preventing the nazi's advance.
</span><span>From the western front, the western Europeans allies fought to stop the advance from japanese and italian army.</span>
