In some respects the Roman Republic was two thousand years ahead of its time. When the Republic was brought to an end by the first charismatic general able to command the allegiance of the masses (Julius Caesar during the civil war) a new political concept for humanity started by Plato and Greek inspiration came to an end. Humanity for most of its history civilizations had imperial rule Athens and other Hellenic Greek states were not like that. What followed the civil war was nearly 1800 years of imperialism across the globe except where tribes were too primitive and small for empire.
Looking at history this way creates a new window for the analysis of the past. Christianity served after the end of the Roman Republic as the model for democracy. The election of a pope instead of family inheritance or pure force to rule was the norm even after the rise of the Roman Empire.
During war the Republic that often had twin Consuls in a shared-Presidential kind of role were placed under the power of a Dictator who ruled the nation for one-year terms until the war was concluded. The role of Dictator for war is obsolete in the modern age for the United States at least, although China has a president for life who has power somewhat like a dictator.
A pope had the power to rule after election something akin to that of a Roman Republican dictator who served for a year during time of war. The Pope’s power of dictatorship in a Holy War against the realm of Satan continued until the Protestant Reformation when Christian leadership from the generally democratic Catholic Church splintered into a constellation of non-imperial political self-determination as well as spiritual self-determination under the Lord Jesus Christ and God. Christian leaders became founders of democracies and imperialism was rolled back over the course of centuries.
In the modern era the success of capitalism is a renewed threat to democracy. Concentrated wealth brings political power and laws of advantage to the richest citizens as they form a global neo-imperial empire wherein all except the one percent and their ten percent professional class of insulators have little political power and a fraction of national income.
The correction of the trend toward a proletariat ruled by an elite may be difficult to reverse because of demographics of the planet, limits to material productivity increase and the fact that capital increases at 4 to 5% annually while growth of productivity increasing at a half-percent as is necessary to conserve non-renewable resources means that concentration of wealth is self compounding at a much faster pace than productivity. Capital increases and high-level wages benefit 10% and less of the people while world ecological health decreases and people have little real power to do anything about it. Maybe the ancient Roman Republic could provide examples and ideas for how to reform U.S. politics in time to save national sovereignty, democracy and environmental viability.