Mortal Republic: How Rome Fell into Tyranny. By Edward Watts.Basic Books; 352 pages; $32. To be published in Britain in March; £25.

S HAKESPEARE MISSED a trick. His version of Julius Caesar’s funeral does, admittedly, have its moments. But he might have done even better had he read his Appian. For while the Bard’s version musters oratorical verve, the historian’s offers a coup de théâtre, complete with the astute use of props, sightlines and stagecraft.

Before the funeral, well aware that Caesar’s corpse would be obscured by the throng, a wax cast of the body was prepared, with each of the assassins’ blows marked on it clearly. This was then erected above Caesar’s bier. As the Roman people filled the Forum, a mechanical device rotated the model slowly, revealing the 23 “gaping” wounds to everyone. The crowd, as they say, went wild.

Caesar’s reign—and its bloody end and bloodier aftermath—would later come to be seen as a turning point in the history of Rome. And indeed it was, but as Edward Watts points out in “Mortal Republic”, the Republic had been in its death throes for decades. The decline was caused less by gaping wounds than gaping inequality, and by leaders unable or unwilling to remedy it. If that syndrome sounds familiar, it is meant to. Mr Watts says inquiries about how antiquity can illuminate the “occasionally alarming political realities of our world” prompted his reflections.

This ominously titled book is his response, furnished with such nudgingly apposite chapters as “The Politics of Frustration” and “The Republic of the Mediocre”. His gambit isn’t new: the classical world is often used as a lens through which to examine modernity. Want to understand China? Read Thucydides. Need to know about Afghanistan? Best study Plutarch. This trick can easily go awry: the past was not just the present in togas, as some historians would do well to remember. But Mr Watts pulls it off deftly.

He begins by taking the reader on a brisk march through Roman history. The Republic’s early citizens were legendarily hardy. In the late third century BC , faced with multiple threats, Rome entered a state Mr Watts describes as “an ancient version of total war”. Two-thirds of the male citizen population between 17 and 30 years old were enrolled in the army, ready to die for Rome. And die they did, cut down in battle after battle like fields of wheat. During one engagement with Hannibal, tens of thousands were killed. The Roman response was to regroup—and win.

Such sturdiness didn’t last. By the second century BC , the formerly united Republic had been split into two factions—not by war but by wealth. On one side was a class of “superwealthy Romans”, enriched by military conquest and growing financial sophistication. They dined off silver plate, ate imported fish, drank vintage wine and holidayed in extravagant Mediterranean villas. One of the most powerful was Crassus, a man who made his fortune in unscrupulous property deals, then used that money to buy political influence.

Yet while some Romans swilled from ornate goblets, the majority drank a more bitter draught. They endured a life of backbreaking work and the knowledge that they would almost certainly end up poorer than their parents. Such a situation could hardly last—and didn’t.