After returning to the East Coast in 1921, Sidis was determined to live an independent and private life. He only took work running adding machines or other fairly menial tasks. He worked in New York City and became estranged from his parents. It took years before he was cleared legally to return to Massachusetts, and he was concerned about his risk of arrest for years. He obsessively collected streetcar transfers, wrote self-published periodicals, and taught small circles of interested friends his version of American history. In 1933, Sidis passed a Civil Service exam in New York, but scored a low ranking of 254. In a private letter, Sidis wrote that this was "not so encouraging". In 1935, he wrote an unpublished manuscript, "The Tribes and the States", which traces Native American contributions to American democracy.