Lex Licinia Mucia...
Since my friend Kahunah and I were talking about our being the new Roman Republic, I wondered how we'd do with a look at the law Rome introduced on their own Latin immigration problem. Rome's Latin neighbors had over the years been granted certain rights, and were often drafted into the Roman armies -- they took a heavy casualty loss at Arausio in 106 B. C. Some even married Romans.
In 95 B. C., the consuls Quintus Mucius Scaevola [the Pontifex Maximus] and Lucius Licinius Crassus [the famous orator] introduced a law expelling the illegal immigrants who had connived to get their names onto the previous census done by Marcus Antonius and Lucius Valerius Flaccus. M. Antonius and L. Flaccus, as censors, had the task of counting all the citizens of Rome.
Antonius had a son by a non-Roman woman, and the son was named Gaius Antonius Hibrida [hybrid son of a citizen father and non-citizen mother], who was to be consul 63 B. C., colleague of Cicero and prosecuted by Caesar.
Special courts were also enacted by the consular law, presided over by ex-consuls who went out to the Italian cities to find who was and who was not illegially enrolled.
Eventually, the Italian allies went to war with Rome, and in the end, Lucius Julius Caesar, consul of 90 B. C. censor the next year [and cousin of a more famous Julius Caesar], carried a law granting citizenship to all Italians not having taken up arms against Rome -- to the consternation of conservatives who decried the amnesty being granted.