My post last night was based on the widely-reported but seemingly incorrect claim that the Senate was currently in recess, allowing the President to make a recess appointment to fill the vacancy on the Supreme Court created by the death of Justice Scalia.
In fact, it appears that the Senate will be holding pro-forma sessions during the break. Under the Supreme Court decision in NLRB v. Noel Canning, such sessions, even if no legislative business is done, establish that the Senate is not in recess:
For purposes of the Recess Appointments Clause, the Senate is in session when it says that it is, provided that, under its own rules, it retains the capacity to transact Senate business.
That same decision found that, in general, the Senate must be out of session for at least 10 days for a recess appointment to be valid. Thus it would appear that, if Sen. McConnell is really determined to stonewall an appointment, the President cannot use the recess-appointment power to tunnel under that stone wall.
However, at least according to one reading of the decision, the President and his Democratic allies in the Senate have the ability to make the maintenance of that wall intolerably expensive, in political terms, and give everyone a huge horse-laugh at the Republicans’ expense. I think they should do so.