^ Then again, if Braxton never went back, then Voyager
never did either, and thus Braxton DID go back...and that way lies madness.
Besides, didn't Janeway think that the Federation's entire technological base owes its existence to Henry Starling's reverse engineering of Braxton's ship?
Side note: There is a model of the Botany Bay
(with its booster rockets) on Rain Robinson's desk in this episode. So the 'alternate timeline' suggestion would not seem to be the case. There never was any proof, or even a suggestion, that the USA was ever involved in the Eugenics Wars in the first place, after all...