The U.S. Constitution owes a huge debt to ancient Rome. The Founding Fathers were well-versed in Greek and Roman History. Leaders like Thomas Jefferson and James Madison read the historian Polybius, who laid out one of the clearest descriptions of the Roman Republic’s constitution, where representatives of various factions and social classes checked the power of the elites and the power of the mob. It’s not surprising that in the United States’ nascent years, comparisons to ancient Rome were common. And to this day, Rome, whose 482-year-long Republic, bookended by several hundred years of monarchy and 1,500 years of imperial rule, is still the longest the world has seen.

Aspects of our modern politics reminded University of California San Diego historian Edward Watts of the last century of the Roman Republic, roughly 130 B.C. to 27 B.C. That’s why he took a fresh look at the period in his new book Mortal Republic: How Rome Fell Into Tyranny. Watts chronicles the ways the republic, with a population once devoted to national service and personal honor, was torn to shreds by growing wealth inequality, partisan gridlock, political violence and pandering politicians, and argues that the people of Rome chose to let their democracy die by not protecting their political institutions, eventually turning to the perceived stability of an emperor instead of facing the continued violence of an unstable and degraded republic. Political messaging during the 2018 midterm elections hinged on many of these exact topics.

Though he does not directly compare and contrast Rome with the United States, Watts says that what took place in Rome is a lesson for all modern republics. “Above all else, the Roman Republic teaches the citizens of its modern descendants the incredible dangers that come along with condoning political obstruction and courting political violence,” he writes. “Roman history could not more clearly show that, when citizens look away as their leaders engage in these corrosive behaviors, their republic is in mortal danger.”

Historians are cautious when trying to apply lessons from one unique culture to another, and the differences between the modern United States and Rome are immense. Rome was an Iron-Age city-state with a government-sponsored religion that at times made decisions by looking at the entrails of sheep. Romans had a rigid class system, relied on slave labor and had a tolerance for everyday violence that is genuinely horrifying. Then again, other aspects of the Roman Republic feel rather familiar.

The Roman people’s strong sense of patriotism was unique in the Mediterranean world. Like the United States after World War II, Rome, after winning the Second Punic War in 201 B.C. (the one with Hannibal and the elephants), became the world’s hegemon, which lead to a massive increase in their military spending, a baby boom, and gave rise to a class of super-wealthy elites that were able to use their money to influence politics and push their own agendas. Those similarities make comparisons worthwhile, even if the togas, gladiator battles and appetite for dormice.seem completely foreign. ...