From Oct. 26: "Cruz suggests leaving SC seat vacant if Clinton elected"
Cruz is the second Republican to suggest that the GOP will simply block any Democratic nominee to replace the late Justice Antonin Scalia, who died in February. Arizona Sen. John McCain made a similar assertion earlier this month.
Speaking to reporters while campaigning for Republicans on Wednesday, Cruz was asked about Supreme Court vacancies.
"There will be plenty of time for debate on that issue, there is long historical precedent for a Supreme Court with fewer justices, just recently Justice (Stephen) Breyer observed that the vacancy is not impacting the ability of the court to do its job, that's a debate that we are going to have," Cruz said, in a quote later provided by his office.
http://www.chicagotribune.com/news/nationworld/politics/ct-cruz-supreme-court-seat-vacancy-20161026-story.html
So there is not only precedent, but a moral duty to ensure Trump's nominees never get in...