Dave,

“Having read Pournelle, Possony [and Kane's] _Strategy of Technology_ helped.”

Indeed, there’s a new footnote in Pournelle’s online version about their estimate of Soviet military spending as a percentage of the economy. At the time, their estimate was far higher than the conventional wisdom held, so they scaled back their number for actual publication. After the fall of the USSR, when actual figures were available, it turned out that their original estimate, the one they were afraid to go with, was actually still an underestimate.