The Authors Reply: We agree with many of the points that James Lindsay and Michael O’Hanlon make in their response to our article. Where we disagree, it is mostly on judgments of the likelihood of various scenarios and the perceptions of future leaders of the value of missile defense systems that now exist only on paper. On the broad spectrum of opinion that deŽnes current U.S. debate over national missile defense—from complete opposition to support for full-scale deployment of a multilayer NMD designed to undermine Russian and Chinese nuclear retaliatory capabilities—our policy conclusions are fairly close to theirs. There are, however, differences in both our analysis and our conclusions that are worth exploring.