Q: What exactly happened?
A: Before today, current senate rules required a three-fifths majority, normally sixty votes, to end debate on a bill, nomination, or other proposal. Without 60 votes to end debate on a judicial nomination, the minority party could block a presidential appointment. Both the Democratic caucus and the Republican caucus have used the threat of a filibuster to block the presidential appointments in the past. But the Republicans have taken it to a new level, attempting to block presidential cabinet appointments (for the first time ever, a party tried to block the appointment of a defense secretary) and blocking 4 of Obama's five nominees to the DC Judicial Circuit Court. In contrast the Democrats blocked one of President Bush's five nominees to the same court.
To launch his missile, the Senate's presiding officer (Sen Harry Reid, D- Nevada) ruled that a simple majority was now necessary to end debate on judicial nominations for all courts except the Supreme Court.
Of course the MAD (mutually assured destruction) that kept either party from using the nuclear option was that with the country evenly divided the party in majority can quickly become the party in the minority with the inability to block the other party's particularly offensive judicial nominees. However, with the Republicans blocking all three Obama nominees to the DC circuit this month, Senator Reid and the Democrats did their best Popeye imitation and said that "they had all that they could stands, and they can't stands no more" and fired their nuke.
Today history changed. As to the effects, we will have to wait and see. For more on just how the Senate runs, read Robert Caro's masterful "Master of the Senate" which detailed how Lyndon Johnson ran the senate when he was the majority leader.
Tomorrow: 11/23/1963 and Frame 313.