Nearly 30 years ago, the people of Eastern Europe were freed from the yoke of communism. Their liberation is a reminder that the Cold War didn’t just end -- it was won. And it was won because the ideas espoused by leaders such as Ronald Reagan, Margaret Thatcher, and Pope John Paul II were far stronger than any army the Soviet Union could ever field. But eternal vigilance, as the saying goes, is the price of liberty. Freedom that is won can, through neglect, become freedom lost. Which is why, since the lifting of the Iron Curtain, America has...