Carthage was one of many cities founded by the Phoenicians in approximately 800 BC. Like Rome, it had a Republican (non-regal) Constitution, which, as described by Aristotle, was a mixed one, with a dominant aristocracy and some oligarchic and democratic leanings.

The Phoenicians came from modern-day Turkey, Syria and Palestine. They were a maritime trading people, possibly because of the poor quality of soil in their native land.

They established colonies, towns and cities across the Mediterranean including the north African coastline, and Spain. it appears their colonisation extended to the Atlantic coast of Africa and Spain.

Carthage was founded by the Phoenician city of Tyrria. In a very fertile part of North Africa (modern-day Tunisia) with a dominating strategic position. Eventually Carthage lost contact with Tyrria as its own power grew, but also because the Phoenicians were pressed by the Asiatic empires of Assyria, Babylon, Egypt and Persia.

Like Rome, Carthage came to dominate the Punic cities through a mix of military might, colonisation and equitable treaties. The Carthaginians also fought nearly constantly against the Greeks in Sicily. Which would ultimately lead to the First Punic War with Rome.

H.H. Scullard speculates that Carthage was founded a republic so as not to encourage the idea that it was disloyal to the Phoenician monarchs.

Aristotle writes:

The Carthaginians are also considered to have an excellent form of government, which differs from that of any other state in several respects, though it is in some very like the Spartan.

Indeed, all three states - the Spartan, the Cretan, and the Carthaginian - nearly resemble one another, and are very different from any others. Many of the Carthaginian institutions are excellent.

The superiority of their constitution is proved by the fact that the common people remain loyal to the constitution.

The Carthaginians have never had any rebellion worth speaking of, and have never been under the rule of a tyrant.

Carthage had a Senate of Three Hundred of which there was a Council of Thirty chosen from the Senate, and as part of the thirty, were included two popularly elected judges called Suffetes. The judges were mainly focused on civil, rather than martial affairs and were elected annually by an assemblic body.

The popular body voted on legislation and policies, but only when the Senate and Council could not reach agreement - such that the popular will became a tie-breaker.

There was also a Council of One Hundred and Four which was purely judicial in focus and was chosen from the Senate. This body was intended to act as check and balance on any tyranny flowing from the other magistracies. It was very close to separation of powers between executive and judicial - but like Rome, tyranny was a real fear, probably because these systems despite the checks and attempts at political balance were often based on arbitrary power.

The Council of One Hundred and Four was appointed, rather than elected, with the appointments done by a group of five magistrates - the Pentarchs. Scullard writes that this led to corruption of the judicial powers until Hannibal flushed out the pentarchs and judges.

H.H. Scullard writes:

The effective government was thus in the hands of an oligarchy of nobles. But it is uncertain how far they formed an aristocracy of birth or of wealth, how far they closed ranks against other aspirants to office, and whether their interests were commercial or agricultural.

Apparently most of what is known about Carthage comes from Roman or Greek writings, which are biased, or from modern archeology. Despite being an Empire and fighting Rome near to defeat through three very long wars it left little mark on the world that was permanent.

Spencer Wells has done several interesting projects that try to fill in the gaps of archeology with genetic science. His documentary Journey of Man discovered that there were two human migratory waves out of Africa. The first ending in Australia, and the second going to Central Asia which led to the population of Asia, Europe and the Americas. He has applied the same technique to see what effect the empires of antiquity have had on genetics - and in particular one of the great seafaring empires, the Phoenicians.

The video excerpts are in three parts.

The Phoenicians came out of modern day Lebanon. That part of the world was pretty restricted agriculturally by the thin strip of arable land. The Phoenicians turned to the Mediterranean and seafaring instead. Their aptitude in this area led them to the Atlantic coast of France and Britain as well as Africa.

Carthage was Rome's great military rival and took two wars of over half a century each to be beaten by Rome. The etymology for Carthage is Qart Chadascht or 'new city'. It was a Phoenician colony from Tyre. However, Wells comments that they found less than twenty percent and possibly as few as ten percent of modern day Tunis carries Phoenician markers in the Y chromosome.

Essentially the Phoenicians did not colonise so much, but take over politically and culturally assimilate indigenous populations. This makes sense as seafaring was a capital intensive and dangerous enterprise in antiquity where moving large populations by sea had low probability outcomes.

This may also hold a key to the origins of the Etruscans. Currently there are two theories for Etrusca. One, that the Villanovans of Italy advanced their cultural and technological output into becoming what we know as Etrusca; or two, a Phoenician colonisation attempt where the Phoenicians, as a culturally and technically superior civilisation, established themselves as the new ruling aristocracy in the Etruscan city-states.

As Wells said, the Phoenicians didn't have a large genetic impact but they did change the culture, very much so in North Africa and Iberia. But IMO extrapolating from the process, maybe Etrusca too? I am sure that Wells and others have thought of that possibility and are probably trying to find some small population they can test to prove or disprove that hypothesis.