Modern technique, not only through the rapidity in the transmission of messages, but also through railways, telegraph, motor traffic, and governmental propaganda, has made large empires much more capable of stability than they were in former times. Persian satraps and Roman proconsuls had enough independence to make rebellion easy. Alexander's empire fell apart at his death. The empires of Attila and Jenghis Khan were transitory; and the nations of Europe lost most of their possessions in the New World. But with modern technique most empires are fairly safe except against external attack, and revolution is only to be expected after defeat in war.
Source: Power, 1938.
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