Much more likely that there would be a blockade...and quite possibly some significant airstrikes...but not an invasion.

You guys who say that there isn't room there for 40 major warships...! To the contrary, there is plenty of room in the Persian Gulf for such a fleet. You are greatly overestimating the amount of water necessary to hold 40 ships and allow them to do battle maneuvers. ;-) You'd be amazed how small the largest ship looks when it's floating on any reasonable sized body of water. The Persian Gulf could hold 500 such ships if it had to.

The main reason for concentrating that many ships in the area would be:

1. to intimidate the Iranians, the Russians, and the Chinese.

2. to increase the amount of shipborne airpower and other firepower in case of launching massive attacks on Iran.

I find the stuff about the Iranian biowarfare not too believable, but (shrug) what do I know about that? Not much.

I think the US administration may be hoping to provoke or panic Iran into launching a first strike of some kind. Or if they can't provoke them into it, well, they can always just pretend it happened anyway. That approach worked fine for LBJ in Vietnam. If the "enemy" won't cooperate and attack you...just lie and say they did.

Or...maybe they are just planning a blockade, period...but I sort of doubt that. Bush only has a few months left to realize his dream. That puts the pressure on.