Under Article II, Section 2 of the Constitution: The President shall have power to fill up all vacancies that may happen during the recess of the Senate, by granting commissions which shall expire at the end of their next session.
Courts have interpreted "recess" to mean a ten or longer-day gap between sessions of the Senate. That means Obama, during the recess, could appoint Merrick Garland to the Supreme Court, since by adjourning for the year on December 9, the Senate will be gone for far longer than ten days.
Can Trump lean on them to do this? Or are they going to do the usual RINO surrender monkey act and we have to bite our nails for a month?