Stop me if this sounds familiar. According to Harvard historian Charles Maier in his new book, Among Empires: American Ascendancy and its Predecessors, empires grow out of “clinging to choices made early on whose reversal seems unthinkable. The imperial project is sustained, not because its advocates always press it further, but because even the hesitant can see no ‘responsible’ way to liquidate it.

An empire can be a democracy too, he thinks, but with one key qualification.

“As in the France of the Third Republic or in Victorian Britain or post-1945 America,” he writes, “it increasingly cordons off overseas military and intelligence commitments from the scrutiny of representative assemblies.”

Indeed. Remember, Bush’s NSA spying is condemned only because his proposed wiretaps weren’t submitted to the secret rubber-stamp court established by the 1978 Foreign Intelligence Service Act. Maier’s point would hold even if we had a law-abiding president.