Of course withdrawal is an option. Otherwise, we give the trump card to Sharon. And if Italy or France had EX Trotskyites in their Cabinets, we would have been crazy to put Americans in harm's way to defend them. America First.
We would have defended France, Italy, and the rest of Western Europe with everything we had, their ex-Stalinists notwithstanding. Better to have a few ex-Stalinists in the parliament than a horde of actual Stalinists in occupation.
Sharon is exploiting the situation, no doubt about it. He knows we can't back out of the alliance. But we have our means of bringing him back into line, and he will only go so far.