Presidents since George Washington have made recess appointments when the Senate is not in session. At the heart of the current dispute is exactly when the Senate is in session.
As Democrats had done previously, Senate Republicans kept the Senate in pro forma session to avoid recess appointments. President Obama opted to challenge the practice in January 2012 when some Republican senators were holding pro-forma sessions while the Senate technically was on a 20-day recess.
When Obama moved ahead with three appointments to the National Labor Relations Board that Republicans considered too labor-oriented, Noel Canning, a Pepsi bottling and distributing company in Washington state and a division of Noel Corp., took the board to court after it ruled against the company in a union dispute. The suit challenged the board's legitimacy.
The case eventually landed in the U.S. Court of Appeals for the D.C. Circuit. A three-member appeals court panel ruled the NLRB's decision was invalid "as it did not have a quorum" because of the invalidity of the recess appointments.
The administration then successfully asked the Supreme Court for review, but eventually replaced the three controversial nominees.
In the Supreme Court Monday, most of the justices appeared to be skeptical of the administration's argument, NBC reported.
SCOTUSBLOG.com reported even some of the liberal justices whose votes the administration needs to support its position appeared to be leaning the other way.
A lawyer for Senate Republicans was allowed to make part of the argument, along with a lawyer for Noel Canning, against the administration's position.