Would a “star wars” missile defence system protect North America from nuclear attack?
It could protect some weapons systems, and it could protect against limited strikes, such as from terrorist groups or from nations like North Korea, but it is highly unlikely that you could ever get a foolproof system. Some key population centres could be protected, but if there was a massive strike, it’s likely some missiles would get through. Another benefit is a certain amount of political leverage, by making it more difficult to engage in an attack on the U.S. They are trying to move away from the mutually assured destruction idea, and if they succeed, the U.S. will increase its power in the international system. Right now, the only leverage Russia has over America is its nuclear capability; if that is weakened, U.S. power and position will increase. How else can we defend ourselves? Security may very much depend on preventing small-scale attacks with good investigation and intelligence about terrorist groups. The ability of cities to evacuate is also critical, as is protecting com