"It may be," says Joseph S. Nye Jr., the Harvard scholar who formerly directed the U.S. National Intelligence Council, "a very rational thought-out message."
Donald Trump's plain speech to Kim Jong-un, delivered hot and loud →
Mr. Nye writes: "China is a long way from posing the kind of challenge to American preponderance that the Kaiser's Germany posed when it passed Britain at the beginning of the last century."
BOOK REVIEW: How America stays No. 1 →