"Men willingly believe what they want to believe." Julius Caesar: De Bello Gallico, Book III, Chapter 18. Dr.SamuelJohnson is quoted by Boswell as using the adage, "The road to hell is paved with good intentions."
The Roman Constitution was an uncodified set of guidelines and principles passed down mainly through precedent. The Roman constitution was not formal or even official, largely unwritten and constantly evolving. Concepts that originated in the Roman constitution live on in constitutions to this day. Examples include checks and balances, the separation of powers, vetoes, filibusters, quorum requirements, term limits, impeachments, the powers of the purse, and regularly scheduled elections. Even some lesser used modern constitutional concepts, such as the bloc voting found in the electoral college of the United States, originate from ideas found in the Roman constitution.
Over the years, the Roman constitution continuously evolved. By 573 BC, the Constitution of the Roman Kingdom had given way to the Constitution of the Roman Republic. By 27 BC, the Constitution of the Roman Republic had given way to the Constitution of the Roman Empire. By 300 AD, the Constitution of the Roman Empire had given way to the Constitution of the Late Roman Empire. The actual changes, however, were quite gradual. Together, these four constitutions formed four epochs in the continuous evolution of one master constitution.