Via Fox News:
There was much hubbub in late 2012 when President Obama made four recess appointments during a short recess between two pro-forma sessions of the Senate in January of that year.
The case later went to the Supreme Court and the maneuver was ruled to be unconstitutional.
The key in the 2014 Supreme Court decision regarding the president’s appointments to the National Labor Relations Board over the three-day break was that the justices found the executive branch determined what it interpreted as a recess.
But Justice Stephen Breyer wrote in the majority opinion that under the Constitution “the Senate is in session when it says it is.”