If it looked like Israel really was finally about to be defeated both militarily and economically while Obama dithered in plain sight, I would not be surprised to see Putin come to Israel military or weapon supplies rescue. This would be done by Putin as an exercise in spitefulness, contrariness and braggadocio to embarrass Obama The Weak, and to begin forming his exclusive, Russian version of NATO.
If it came to that and nobody else came to their aid i would not complain about Russian support in the situation. Would you?