The explosively formed projectiles ...said to have been supplied from Iran to Shi'ite militias are specially designed to attack armored vehicles. Essentially, these devices consist of an explosive designed to deform a block of metal and shoot it forward, still molten, in the direction of the target vehicle. It is like firing incandescent shot at extremely high velocity toward a target. This technology has been used by the US to create top-attack warheads against tanks. The principle has been adapted by the Iranians to attack the vulnerable aspects of armored vehicles.
But it is not simply the weapons themselves, which are profitably employed only against armored vehicles, which betrays their anti-American intent. The explosively formed projectile weapons supplied by Iran are, from what I can gather, also matched to tactical doctrines and methods explicitly designed to counter American countermeasures. The triggering devices are too complex and expensive to be sensibly used against civilian targets. These weapons have only one logical target. Americans.
If detonated correctly these Iranian-supplied weapons will definitely kill or maim Americans as they were designed to do. Passive defenses, like adding armor, are of limited utility...what must happen to IED threats like the explosively formed projectiles and their associated targeting systems[?]. You can't keep bailing the water. You have to turn off the faucet.
If Iran insists upon sending U-Boats -- pardon, explosively formed projectiles -- to attack Americans, it is effectively opening hostilities on the US. That politicians in Washington choose not to regard it as such is not really Teheran's fault. One can accuse the Ayatollahs of many things, but creating American indecision cannot be blamed on them. That is the result of politics along the Potomac.