WITH TIME, the readerly self comes to feel about books much the way Barbara Woodhouse must have felt about dogs after all those many years of warbling "walkies!": wary rather than hopefully expectant and willing to brook no nonsense, yet still capable of surprised pleasure and even, on rare occasions, joy. My heart still rises when I open a book I'm eager to read, and in that Woodhouseian, no-bad-dogs moment there can be no bad books.

But, sadly, there are. Disaffection with a given title reveals itself in many ways: one does not respond to the opening pages, one senses the author has no feel for language or is somehow not simpatico, one notices – especially in the case of ballyhooed novels – that matters go discouragingly south after a hundred pages or so, which is just about the point the author was likely paid a huge advance to finish a project he or she had no idea how to finish.

Other titles disintegrate more insidiously. I began Jim Garrison's America as Empire: Global Leader or Rogue Power? (Berrett-Koehler, $24.95) with open-minded curiosity but felt an immediate shiver of unease at the author's incantatory, and I suspect unconscious, repetition of the word overwhelming to describe the United States' military capabilities. When, deeper in the book, I found myself reading a salute to imperial Roman rule as "noble," I simply could not go on.

A few springtimes ago on a hot May morning, fresh off the train from Trajan's second-century port at Civitavecchia, Italy, I stood in the fori imperiali – the vast archaeological trench that stretches more than a mile from the Colosseum to the Victor Emmanuel monument – and found myself seeing not the remnants of the wonders of the ancient world but the savagery of it. When we think of imperial Rome, many of us think first of magnificent marble-columned buildings, but the marble was just a façade (much of it later stripped and carted away to build the Vatican); the old city was really built of brick – countless tens of millions of waferlike bricks – and those bricks were made and laid by countless slaves.

Noble? Rome was founded on slavery and military conquest. Its emperors tended to be generals; in our day this arrangement is called, not admiringly, the junta. Assassination was routine. Garrison suggests Roman rule was widely seen as "just and fair" by those subject to it, but I assume he is not referring to the citizens of Corinth, whose city was obliterated for refusing to be subjugated, nor to the Jews, who somehow survived two Roman wars of extirpation launched against them.

The democratic traditions of the north of Europe, meanwhile, are overlooked or forgotten, despite their venerable roots and persistent vitality. Garrison aligns himself with conventional wisdom by dismissing the Germanic tribes on the far side of the Rhine as "barbarians," but many of those tribes, though given to such slight quirks as fighting in the nude and hunting for heads, elected their kings. Europe's oldest parliament is Iceland's Althing, which has existed for more than a millennium. It was at Runnymede, England, in 1215, that King John was obliged to sign the Magna Carta and, by so doing, to accept codified limits on the divine right of monarchical – which is to say, unaccountable – rule. Not too shabby for barbarians. Of course, Italy was still sunnier.

Garrison says we should "celebrate" our "global mastery" and "the world should modulate its antipathy toward America" – if not actually celebrate with us – because we are "so benign," notwithstanding the bases, the bombings, the bluster and bullying, the occasional invasion. He is less ridiculous than he sounds, for it is clear that despite two centuries of republican and democratic treacle, dreams of empire have never been far from our thoughts. One need only look at the marble colonnades of Washington, D.C., and briefly review our history of constitutional slavery to see that our model was Rome from the outset.

Question that pro-imperialists never ask: is empire good for us? What benefit, if any, from a worldwide military presence and a perennially swollen military budget redounds to the citizens of the United States? As Ronald Reagan himself might put it, are we better off minding everyone else's business than we would be if our government minded its own business, looked after the welfare of its own citizens, constituted a military suitable for the defense of American shores instead of the invasion of the shores of others, and accepted that we have no moral or political warrant to decree how other peoples and nations should organize their affairs? Is it really so ignoble to wonder these things?