But still, Green's theorem says something.
Here's what it says:
You don't have path independence, but Green's theroem tells you how the value of the line integral changes when the path is changed.
Suppose C is a given open path, and that D is another simpler path between the same initial and final points. The the path C - D is closed, so Green's theorem can be applied. Let Omega be the enclosed region. Then: