Crooked Hillary!

Uh no it can't?

It hasn't been done in a long time, but yes a president can do that. I believe the Senate can actually block it if they specifically vote on it, but it's not just an automatic thing, they have to actually make the decision that it can't happen BEFORE it is done in order for it to be blocked. Pro-forma sessions or something? They actually did that this time to preemptively block Merrick Garland (just in case Obama was actually self destructive enough to do it) I think, now that I'm looking, and they also did it in 2005 (I think, I know it was sometime at the end of his second term) with GWB.

Article II, Section 2 of the U.S. Constitution provides that:

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.

Thus, when the Senate is in recess, the President may make a temporary appointment to any office requiring Senate approval, including filling vacancies on the Supreme Court, without the Senate's advice and consent. Such a recess appointee to the Supreme Court holds office only until the end of the next Senate session (at most, less than two years). To continue to serve thereafter and be compensated for his or her service, the nominee must be formally nominated by the President and confirmed by the Senate. Of the ten Justices who have received recess appointments - two Chief Justices and eight Associate Justices - only Chief Justice John Rutledge was not subsequently confirmed for a regular appointment. No president since Dwight Eisenhower (who made three such appointments) has made a recess appointment to the Supreme Court and the practice has become highly controversial even when applied to lower federal courts. During the 110th Congress, the Democratic leadership of the Senate specifically blocked Republican President George W. Bush from making any recess appointments with the use of pro forma sessions.

In 1960 the Senate passed a resolution stating that it was the sense of the Senate that recess appointments to the Supreme Court should not be made except under unusual circumstances.

The reason this is a loophole is because of that final clause, except under unusual circumstances, otherwise this sort of thing is indeed not possible at all.

Can I just say that anyone complaining about the constitutionality of Obama's unilateral use of executive orders should be equally appalled at the Republican Senators for blatantly ignoring their constitutional obligation to confirm supreme court justices. They can reject candidates, but they shouldn't be allowed to ignore them indefinitely.

Not arguing that, they should at the very least vote them down if they are going to, and not just leave them hanging there, it's stupid and a waste of time.