According to the Huffington Post,
Seeking to reassure the questioner that he has only the best intentions for fans of hardcore conservative judicial activism, [McCain] told the questioner that there were going to be two-to-three vacancies on the Supreme Court soon. This was, in McCain's words, "According to people who decide these things."
What in the world could he have meant by that? The Huffington Post thinks he's talking about the Grim Reaper, since Supreme Court justices have life-time appointments. Could be he's just losing it.