Re: Can't they have a word with the Israelis?
Actually the Iron Dome system was meant to have worked remarkably well with very few missiles getting through and hitting human occupied areas. The system is clever enough that on detecting an incoming missile it will calcualte where it will land and if that's waste land, desert, the sea, etc, then it will leave it be and save the missile for the next potential target.
As others have said, it is only a defence against short range missiles (though theoretically also agaisnt SCUD type) and is part of a three tier solution. Middle tier will be the replaement for patriot (which had only about a 50% success rate during the Gulf War), and the third tier a theoretical defence agaisnt ICBMs.
Iron Dome is Israeli tech, not a joint project, however I do understand they are looking to sell it to the US.