Briefly, just a couple of technicalities. One cannot have any discussion of Perikles’ “Citizenship Law” isolated from, broadly, 1) the nature of what the πόλις was to ancient Greek civic identity; and more narrowly 2) the unprecedented success of the Delian League, and the population explosion Attica experienced during the Pentekontateia.
This doesn’t need much exposition to lay a more complete universe of discourse:
Aristoteles (Pol. 1260b40-b1a1; 1274b-38–75a2, b18–20 et elii). In short, the πόλις was a body of persons adequate to achieve αὐτάρκεια (self-sufficiency). Self-sufficiency became the paramount defining aspect of any πόλις.
The members of a particular πόλις and the nature of the ἀρχή (office-rule [Greeks did not separate the concepts]) they practiced defined its πολιτεία — an exceedingly difficult word to render in English — but for our purposes here: “the nature of the καθεστώς (regime-status quo [again, the Greeks did not separate these concepts]).”
In other words, πολιτεία does not separate the members of a πόλις from the form the καθεστώς or πόλις took. Thus, one should probably render πολιτεία as “citizenry-constitution.”
The πόλις became the civic centers for specific regions that grew out of a cluster of houses or clans or tribes, and “reciprocity” among and between these groups rests at the core of each πόλις.
More importantly, “real Athenians,” and this concept is NOT difficult to understand (and we don’t need to wonder off into the weeds regarding autochthonous myths), were those οἶκοι (households) that descended from the original Attic φυλαί (another exceedingly difficult word to render in English but essentially “institutional clans”).
Their members shared “customs and dialect” and thus thought of themselves as the true “insiders” — versus “outsiders,” but, during this time, outsiders were not only those from “outside Attica” but those from another φυλή as well.
Problems arose, because φυλαί were notoriously lax in enforcing exclusion, something that Solon recognized. These early “outsiders” had become ἑκτήμοροι or πελάται (tenants or dependents) and from there eventually “insiders” through marriage to insider households.
In the case of Athens specifically, the concepts of ξένος (foreigner, lit. “stranger”) and μέτοικος (foreign resident, lit. changed household) did not even exist as legal distinctions prior to the 6th century. And, when they do appear, they are exactly that: legal distinctions.
I thus see a too casual equivocation between ἔθνος and πολῑ́της. The latter was a specific status defined by the laws-customs of a particular πόλις.
Despite the inherent differences between each of the πόλεις, all Ancient Greeks worshiped the same gods and spoke the same language. They also farmed and fought in the same manner, held several Panhellenic Festivals (e.g. Olympia, Eleusis), and, while individual πόλεις adamantly protected their independence, they still all thought of themselves as a single ἔθνος.
Within this ἔθνος were clearly understood cultural subdivisions (Ionian, Dorian, and Aeolian for example), which were defined primarily if not exclusively by language (dialect). Any Athenian who traveled to Corinth or Sparta would be recognized as “Greek” but they would not enjoy protection under Spartan or Corinthian laws.
In short, Athens did NOT restrict any ἔθνος from coming to Attica (and in many cases invited some), but rather restricted a person from becoming a πολῑ́της. I opine that critical distinction gets lost in the article.
The unusual and totally unprecedented success of the Delian League, and Athens’s command of the sea, fostered trade on a scale never before seen in the Aegean.
Attica experienced a very real “population explosion” from ca 460 BCE to the time of the Great Plague — an explosion, which the Laws of Solon did not foresee (or, perhaps more accurately, could not address adequately). In fact, no πόλις had experienced such phenomenal growth in Hellenic history.
On the other hand, Athens not only founded colonies to rid the πόλις of a growing and idle population (made up of poorer Athenians, foreigners, and slaves), but also established κληρουχίαι (lot-holders) of Athenian citizens they settled on foreign soil.
A quite large group of Thracians, on teh other hand, were granted unparalleled privileges to hold both a public festival and own a private cult as well as own land in Peiraieus (you see this group in the Opening of Platon’s Republic).
As with any successful regime, Athens fiercely protected access to the privileges its citizens enjoyed. It only expanded the franchise when desperately needed: for example, the Athenian assembly bestowed “citizenship” on all slaves and foreigners, who fought at Arginousai
This concept of the πόλις also explains why the very first action of Athenian oligarchs (Peisistratos, the Four Hundred then the Five Thousand and then the Thirty and the Three Thousand) was invariably to restrict the Athenian franchise, and this began with the Athenians — not with foreigners or resident aliens.
The seizure of Lysias’ property (and other metics), for example, came late during the rule of the Thirty and the threat of civil war.
Nevertheless, the Thirty executed Athenians first. Metic property and executions did not take place until and only after Lysias had hired mercenaries to support Thrasyboulos’ forces at Phyle. The Thirty then chose those foreign residents who had spoken out against the Thirty.
By the end of the Athenian Civil War and the Fall of the Thirty, all arguments for and actions taken regarding the Athenian franchise (who received what) focused first on participation in events prior to and during the rule of the Thirty.
Approximately 1,200 foreigners received ἰσοτέλεια, which freed them of taxes, gave them license to own land, and bestowed judicial standing … what they could NOT do, however, was vote.