"Here is an open acknowledgement by Mr. Liu that a judge should use his position to advance his own views," McConnell said. "This is repugnant."

He spoke minutes before the Senate failed to invoke cloture on Liu's nomination by a 52-43 vote in which Sen. Orrin HatchOrrin Grant HatchGOP eyes limits on investor tax break Children’s health-care bill faces new obstacles Overnight Finance: White House requests B for disaster relief | Ex-Equifax chief grilled over stock sales | House panel approves B for border wall | Tax plan puts swing-state Republicans in tough spot MORE (R-Utah) voted "present."

Like other Republicans, McConnell argued Liu has no experience as a lawyer or judge, and that the Senate must therefore judge him on his writings, which they said indicate Liu would tend toward liberal judicial advocacy.

"In his view, it is the job of a judge to create new rights regardless of what the Constitution says or what the American people acted on during the democratic process," McConnell said.

He added that there is a risk Liu might consider non-U.S. law as a judge, based on his comment that the U.S. does not have a monopoly on wise solutions to legal problems.

"This might fly in a left-wing classroom, but it's cold comfort to those who look to the courts for equal justice under the law," McConnell said. "Americans shouldn't have to wonder when they walk into an American courtroom which nation's law they will be judged under."

This post was updated at 2:54 p.m.