I was going to say Poland, but that would imply that they would have allies in the west that would go to war if they were invaded, which seems unlikely.
In 1938 Czechoslavakia was completely sold out by Britain and France in Munich to the Nazis when they were forced to give up their fortified border regions to the Third Reich, which would be required for any serious defense of their nation from a German invasion. In the end Czechoslavakia was invaded anyway, with the Bohemian region being more or less annexed and the Slavak region being divided between a Slavak puppet and Hungary.
Could history be repeating itself? Is Israel being set up for failure?