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For the first time in seven decades, we live in a world without global leadership. In the United States, endless partisan combat and mounting federal debt have stoked fears that America's best days are done. Across the Atlantic, a debt crisis cripples confidence in Europe, its institutions and its future. In Japan, recovery from a devastating earthquake, tsunami and nuclear meltdown has proven far easier than ending more than two decades of political and economic malaise. A generation ago, these were the world's powerhouses. With Canada, they made up the G7, the group of free-market democracies that powered the global economy. Today, they struggle just to find their footing.

Not to worry, say those who herald the "rise of the rest." As established powers sink into...