“In the Soviet Union, for example, shooting or jailing political opponents at first helped the Communist Party and then Josef Stalin gain absolute power. But after there were no visible opponents left, seven million more people were executed, and many millions more died in the far-flung camps of the gulag. So many engineers were seized that factories came to a halt; so many railway men died that some trains did not run; so many colonels and generals were shot that the almost leaderless Red Army was nearly crushed by the German invasion of 1941.”