Gang of 14, Appointing Federal Judges

McCain is talking about the Gang of 14. This “gang” is highly controversial, created to circumvent the Constitutional requirement of a straight up and down vote on the appointment of federal judges. The Gang of 14 consists of fourteen senators who–ostensibly–were going to prevent filibusters which would result in blocking these judges. Contrary to common understanding, the group didn’t block the approval of qualified judges. The “gang” guaranteed that three specific judges would be appointed to the courts.
You can read the ultra-conservative National Review’s condemnation of the Gang of 14, and particularly John McCain’s role, here.