As the walrus said to the carpenter in Lewis Carroll's fable, "the time has come to talk of many things." In Israel, after the pounding Israel's citizens in the south took from assorted rockets and mortar shells in the past weeks, the time has come to talk of that great Israeli development, the Iron Dome rocket interception system.

It successfully engaged a good number of rockets launched from the Gaza Strip against the south, and was a source of justified pride for all Israelis. But before we make this system the linchpin of Israel's defensive strategy it might be well to analyze the performance of the system during the recent attacks, and the final result. Who was the winner in the duel, the Iron Dome or the combination of Grads, Qassams and mortar shells fired against the civilian population in southern Israel?

The Iron Dome, developed by Rafael, is a superb technological achievement. It follows Israel's first technological breakthrough in ballistic missile interception - the Arrow, developed by IAI. For years the interception of ballistic missiles was considered next to impossible, until the Arrow, designed to intercept missiles launched from a distance of hundreds of kilometers, proved otherwise.

Obviously, intercepting missiles launched from shorter ranges is a far more difficult task. The Iron Dome is capable of intercepting ballistic missiles launched from a distance of 5-70 kilometers, no mean feat. It is an achievement unequaled anywhere in the world. All Israelis can take pride in this achievement. Over and above its military value, and it has substantial military value, it enhances Israel's image in the eyes of friends and foes alike.

As should be expected, it is a very expensive system, which at this point intercepts simple, very cheap, rockets. If valued in terms of out-of-pocket costs, for attacker and defender, it cannot win the battle against the incoming missiles. But, of course, that is not the only consideration in acquiring the system.

An Iron Dome battery is capable of providing defense for an area of about 150 square kilometers against incoming ballistic missiles. That is its "footprint." That means that it cannot provide protection for all of the Israeli civilians living in southern Israel, even if a substantial number of additional batteries were added to the two batteries presently deployed. Also, if a large number of rockets are directed into the area protected by an Iron Dome battery the system can be saturated, and thus penetrated. It does not provide protection against mortar shell launched at short range. In other words, it is only a very partial answer to the rocket threat against Israeli civilians coming from the Gaza Strip.

This became clear last week. The incoming rockets forced Israelis throughout the south to run for shelter. That is the bottom line - and in that sense the rockets were the winners in the duel with the Iron Dome. The terrorists in the Gaza Strip understand that, and more rockets will surely be coming our way. Thus the Iron Dome is a source of pride and gives us the feeling that we are not completely helpless against the rocket threat. It gives mayors in the south a chance to compete against each other in pressuring the government to acquire more Iron Dome batteries and deploy them near their cities, and it seemingly provides justification to increase the defense budget.

But to be honest, whereas the Iron Dome can effectively defend small militarily important targets, it does not provide the protection that our civilian population in the south, and maybe tomorrow in the north, is entitled to. The idea that missile interception systems, when eventually deployed throughout Israel, will provide an impenetrable umbrella under which Israelis will be able to peacefully carry on their daily lives even when Israel is attacked by rockets, is an illusion. There are other ways to put an end to the rocket threat, and the government will sooner or later have to resort to them.