As Wikipedia explains: "In the 1840s, over 130,000 Irish immigrants arrived in New York City to escape the Great Famine, arriving in poverty and joining scores of thousands of their fellow countrymen who had arrived over the prior decades. By 1855, 34 percent of the city's voter population was composed of Irish immigrants. By providing these new arrivals with patronage employment, job referrals, legal aid, food, shelter, employment insurance, and other extralegal services, including citizenship and naturalization services, Tammany secured the lifelong support of the large and growing Irish population, which would form the majority of its electoral base for the next century. In exchange for these services, the Tammany political machine harvested Irish immigrant votes."

The article also quotes Plato, who predicted Tammany Hall 2,400 years earlier. Plato saw good government as a precarious and fragile thing that could be achieved only through careful cultivation of the polity's "constitution"--not just a legal document, but the political "way of life." As a result, Plato's ideal city had strong borders and was insulated from both trade and immigration: https://spectrum.library.concordia.ca/id/eprint/983154/1/EXO....

"In most states of course, such confusion is a way of life with which people learned to cope by various compromises, as was the case when immigrants are allowed into a country (PS, 293d). But such compromises were neither necessary nor desirable for Plato, since any policy of unrestricted immigration would destroy his political constitution (PL, 736c; 950a). Aristotle agreed that immigration was a dangerous thing because it pitted newcomers against those already established, thus creating tensions and frictions between them."

Plato's Republic describes a society's descent into anarchy as involving the erasure of distinctions between citizens and foreigners: "the metic" (legal permanent resident) "becomes the equal of a citizen and the citizen of a metic, and similarly with the foreigner."

The author sets up an astute point linking Tammany Hall, Plato, and MAGA republicans, but somehow whiffs the conclusion. The U.S. didn’t defeat Tammany Hall through unspecified “fighting back”—it did so through assimilation and homogenization. The U.S. enacted restrictive immigration law in 1921. That, coupled with a population boom, dropped the foreign born population from 15% to under 5% and largely erased the separate identity of Ellis Island immigrants. That neutering of ethnic attachments made it impossible to sustain political machines that were built on ethnic solidarity.