United States Senator Jon Kyl (R-AZ) made a compelling argument in today’s Wall Street Journal against ratifying the Comprehensive Test Ban Treaty (CTBT).  For nearly two decades the United States has relied on technical extrapolations to verify the reliability of the U.S. nuclear stockpile.  But these technical extrapolations are essentially ”best guesses” based on historical trends and data.  As I said in a recent post, “The only way to be certain a weapon is reliable is to test it.”  Kyl is right when he argues that the credibility of our nuclear deterrent is dependent on the reliability of our stockpile.  As I’ve mentioned previously, as the credibility of our deterrent decreases, friends and allies may be forced to develop their own nuclear deterrents.