Or if you really want to go down the rabbit hole, there's a theory that Donald Trump is a time traveler. Maybe McCain blocked Kavanaugh's confirmation at some point in the future so Trump came back with tech to accelerate McCain's cancer.
Uggh, now my brain hurts.
But seriously, there are people who think Trump is some kind of time traveler. Trump's uncle worked for Tesla and there is speculation that he may have stolen some of Tesla's private papers upon the death of the reclusive genius, including plans for a time machine.