Further demonstrating that Tehran is controlled by a murderous, irrational regime bent on our destruction, the number of roadside bombs and explosive devices in Iraq has plummeted to its lowest level in years, largely because Iran has stepped up the policing of their own borders and staunched the flow of weapons into Iraq. Of course, if we decide to bomb Iran, those weapons will flood back in, and they will be aimed at our troops.
It would seem that Iran is demonstrating something fairly simple in all this: So long as we're in Iraq, they can be our ally, policing the flow of weapons and convincing various Shiite groups to act constructively, or our enemy. Were Iraq half as important as George W. Bush says it is, we'd be seeking friendlier relations with Iran if for no other reason than to actively engage them in Iraq, as their benign engagement is a crucial ingredient for any move towards stability.