US election: Could Republicans still dump Donald Trump?

For all Republicans out there longing to boot Donald Trump off the presidential ticket even at this late stage, there are four key words.

Death, declination, or otherwise.

The Republican National Committee (RNC) sets out in its Rule 9 the terms for "filling vacancies in nominations".

It reads: "The Republican National Committee is hereby authorized and empowered to fill any and all vacancies which may occur by reason of death, declination, or otherwise of the Republican candidate for President of the United States."

Death may be off the agenda, so what about the other scenarios?