Tammany Hall is a game of backstabbing, corruption, temporary alliances and taking power at all costs. If you want to rule New York, you are going to need to play the cities growing immigrant populations against one another. Help the immigrant groups who owe you political favours, call in those favours to slander your rivals and win election.
Tammany Hall was the political machine that dominated New York City politics by organising the immigrant populations. While the organisation's influence spanned from its founding in the 1790s to its collapse in the 1960's this game is set in lower Manhattan roughly between 1850 and 1870; the era of Boss Tweed.