That doesn't make any sense. The reason SDI is suicide to build is because the countermeasures are ridiculously cheap and compensating for them is ridiculously expensive. It will always be an order of magnitude (or ten) cheaper to build more almost-free decoy warheads than it will be to expand the tracking, targetting, and interception capability of the system shooting down the 'warheads'. You just deployed a system that can handle 100 warheads at once? Next month I'll roll out 100 decoys and 50 legitimate warheads. It'll cost me $2 million and for you to handle an extra 50 will take you years and cost $2 billion. If you want your system to be effective, you have to agree to your own death by economic attrition.