There is no point in writing an alternate history unless you meant to do that. Maybe the ultimate failure of Philip Roth's otherwise brilliant The Plot Against America is that, in the end, it doesn't really mean to be alternate, except for an initiating conceit. But the unexamined alternate history is not worth living. A genuine alternate world/alternate history must be an argument about the case of things, or why bother?
An alternate history is a sentence on the world.
Whether that sentence spells heaven or hell or parole, it is a spell of judgment, or else we are in Faerie, which is another story altogether, something Other. In SF there is no Other but difference, and difference is a speculum. In the radical form of SF known as alternate history that speculum should reconfigure every jot and tittle of the world shown. Any told moment in an alternate world should be as irradiated with meaning as any single shot in a 1940s film noir, where nothing is given that is not meant to be taken.
(Это вступление к рецензии на The Yiddish Policemen's Union Майкла Чабона - роман о