Whom do the two men in the poster represent?

The man on the left wearing the hat is a soldier. The other is a civilian. Since the civilian is standing next to a pile of leaves, it can be assumed that the citizen is growing a Victory Garden, which is growing food at home to provide more food for the soldiers fighting the war. The other soldier is on the other side of the fence. Normally, fences separate, which means that the soldier is separated from home, fighting the war in Europe.
TLDR;
The one on the left is a soldier, while the person on the right is a citizen.