Subject: Re: WHY does Israel have to wait for
Threatening not necessarily, but following through just once will certainly alter their calculus.

"Following through" requires committing a violation of international law and (probably) initiating hostilities against Iran, though. Sinking a vessel that has itself taken no overt hostile action against any of our vessels in the area, presumably killing many (if not most) of the Iranian nationals on board)? It's one thing to call a strike against a military base or against a military leader in direct retaliation for that country's actions against you....but for simply supplying a third party rebel group in another nation? You're kicking it way up the aggression scale. So you can always do that, but you're committing an overt act of aggression in circumstances that don't typically support that kind of attack.

Since Iran's leaders would probably welcome that kind of political gift ("Remember the Behshad!"), the threat is extraordinarily unlikely to get them to change course. And the consequences of the attack are almost certainly more negative for the US than anything we would gain from sinking the ship.