I don't know where the 57 comes from, though I do grok 56. Start with 50 states. Add DC (three electoral votes) and you're at 51. Add Guam, Puerto Rico, American Samoa, U.S. Virgin Islands, and the Northern Marianas territories, and you're at 56.
I can see a professional politico in inclusion mode counting the territories. They don't have electoral votes, but they do vote for in presidential primaries and for territorial and local offices, and they have local party organizations (not necessarily named Republican and Democrat) that organize with the RNC and DNC. They come to the national conventions. A political pro would have them on his radar screen.
Here is the language from Rule 1 of the RNC:
(b) For the purposes of this rule and all other rules, "state" or "states" shall be taken to include American Samoa, the District of Columbia, Guam, Northern Mariana Islands, Puerto Rico, and the Virgin Islands, except in Rule No. 14, and unless the context in which the word "state" or "states" is used clearly makes such inclusion inappropriate.
I can't find the DNC rules on their website. Perhaps I'm overlooking it, but it may be that the Party of the Superdelegates, with its top-down, caucus-dominated, quasi-Leninist structure, isn't anxious for casual viewers to read its rules.
Would 57 be ISLAM?