Many people have drawn parallels between ancient Rome and the modern day United States. How are Rome and the U.S. similar, how are the different, and what can the U.S. learn from Roman history?

Population, especially urban population, declined precipitously from about 150 to 650 because of new epidemic diseases. This is the central fact behind Roman decline, and the changes in government, military, religion, etc. were all in this context. Unless we enter a similar era of population decline, lessons to be drawn are limited.

The similarities just aren't there in the way people claim they are. Rome started life as a city and had a system of government in place to rule a single metropolis. Gradually it expanded to accomodate the entire of what we know call Italy and then became an empire that included most of Europe, parts of Africa and bits of Asia. The United states began as a group of colonies and became a country of united states. It established a constitution to rule the country which has held (with some amendment) for centuries. America has won overseas wars but has never absorbed it's conquests into it's empire. It has stayed as the United states. If Washington ruled and taxed the citizens of South America, Canada and parts of Russia I would think the comparisons stood, especially if they established another capital in Argentina. But the truth is most people who compare America to Rome have no understanding of Roman history.

Well, the similarities are there deliberately. When we became a new country, we obviously wanted the best way to become stronger than our parent country, Great Britain. For this reason, we created a Republic, with notable differences than the Roman predecessor. For example, we have a bicameral system, both a Senate and a House of Representatives. We have a checks and balances system, which ensure that we'll never have a dictatorship or monarchy. Our founding fathers wished for our rise to be quick, which it relatively was, but made provisions to try and make sure that our government got too strong or absolute. This is (at least the way I was taught) where the perception that we are making the same mistakes that Rome made. Our government has become increasingly stronger, and militarily, like Rome, we have risen to the top only to fight in prolonged wars where we no longer need to be, and struggle with geurilla warfare  (which was the biggest Roman weakness).

America has no barbarians (oops terrorists) to fight to stop our inevitable expansion and spread of Pax-Americana.  All roads do not lead to Rome (but they do all go to NYC).  We do not have bread and circuses but we do have football and food stamps.   We do not have a corrupt senate (anyone who believes that I have a bridge to sell you in Manhatten) that has not sold to the noble (oops the Fortune 500) classes.    We have not ceased being a republic yet only because no one has dared take power yet.   If the senate (aka congress) remains dead locked a Caesar may be required.

America is much bigger, but Rome has better food and more old buildings.

A major difference is the speed at which events have unfolded. The Roman Empire lasted over a thousand years and took hundreds of years to unravel. At the current rate of change, the U.S. will be viewed only as a historical artifact in a fraction of that time. Most notable is the demise of democracy. Most U.S. citizens are not even aware that they live in a Plutocratic Oligarchy. Leaders of the silent, bloodless coup have been solidly in control since 2010. This after a fifty year decline as those now in control quietly undermined democracy as codified in the constitution. Those in control achieved this by using influence, campaign contributions and outright corruption to negate the intent of votes by citizens. They have cleverly left the, now meaningless, voting process in place. At the same time they manufacture an ongoing stream of divisive issues to keep the population occupied as they go about the business of accumulating even more wealth and influence. History shows with virtual certainty that such a strategy will end badly for everyone.