It is eerie how most responsible nations loudly condemn Iran's race to get a bomb, but they are just as reluctant to face down Iran as the early 20th-century democracies were to confront Hitler before he became too powerful and confident. Once again we are understandably unsure whether the bad choice of using force now is preferable to the nightmare of using even greater force later.
The wobbly European Union was based on the same 20th-century idealism that once launched the League of Nations and the United Nations. And Europe seems to be following the same tired script of the 1930s. Weak democracies are once again offering moral lectures to rising powers while disarming.
The 20th century's "German problem" was supposed to be a distant memory. But a reformed and democratic Germany nevertheless is once again earning both the envy and fear of its weaker neighbors.
Like 1938 Britain, most of the European Union has no clue how to prevent German economic dynamism from eventually leading to military and political dominance. In early 20th-century fashion, the volatile European street is swinging from hard left to hard right.
Vladimir Putin's Russia is as authoritarian as ever. As in the last century, Israel and the Palestinians still have no peace. Brazil still has unlimited but never-realized potential. Argentina remains the same self-destructive mess. The Arab Spring ended in the same old Middle East chaos.
The 21st-century United States is in a 20th-century fit of depression -- with the decline of America the same cultural motif.
In the 1930s, fascism was purported to be more efficient than American democracy. Then Nazism was said to create more idealistic and disciplined citizens.
After World War II, the new communist man was announced as the wave of the future.
Then came the superior 20th-century model of postwar "Japan, Inc."
Next was the all-powerful European Union.
The ruthlessly efficient Chinese juggernaut followed and seemed destined to outpace 20th-century America -- which was suffering everything from stagflation to a shortage of oil.
But once more, 21st-century America is confounding its critics by reinventing itself as it did last century.
The U.S. may soon become the world's largest gas and oil producer. Food exports are booming as never before. American brands from iPhones and Starbucks to Google and Twitter flood the world.
To find answers for this chaotic young century, just look back at the past one.