<p><span class="deck">A former Department of Defense adviser—one of Robert S. McNamara’s Whiz Kids—explains why we tend to overestimate Russian strength, and why we underestimate what it will cost to defend ourselves.</span></p>
<p><span class="deck">Though it appears to have sprung up overnight, the inspiration of free-spirited hackers, it in fact was born in Defense Department Cold War projects of the 1950s.</span></p>
<p>U.S. military leaders drew up elaborate plans to invade Japan, with estimates of American casualties ranging as high as two to four million, given the terrible losses at Iwo Jima and Okinawa.</p>
