The nominee, Debo Adegbile, ran the NAACP's Legal Defense Fund (LDF) and represented Mumia Abu-Jamal, the former Black Panther Party member tried and convicted for the killing of Philadelphia police officer Daniel Faulkner in 1981.
In 2009, the LDF argued before the Supreme Court that Abu-Jamal's death sentence should be overturned because the jury was biased.
It was. And Adegbile was one of several lawyers defending Abu-Jamal when prosecutors tried to reinstate the death penalty.
"They turned that trial into a circus. They turned this into anything but about Danny Faulkner and the 1300 block of Locust Street that night," said John McGroder of the Philadelphia chapter of the Fraternal Order of Police.
Police unions and Republicans have pounced.
Senator Pat Toomey spoke on the Senate floor with Officer Faulkner's picture nearby and urged his colleagues to vote against the nominee.
"These LDF lawyers promoted the myth that Mumia Abu-Jamal was somehow a heroic political prisoner that we framed. In fact, he was a coward and an unrepentant murderer," said Toomey.
However Adegbile's supporters says the criticism is unfair. They say he's not anti-law enforcement but rather a defender of the most principled institutions in America.
They argue that the fact he represented an unpopular client shouldn't stop his nomination.
In response to criticism, last month the LDF released a statement that reads in part:
LDF is committed to ensuring that the American criminal justice system is administered fairly and without regard to race, such that all individuals charged with or convicted of crimes are afforded the safeguards guaranteed by the Constitution.
Action News tried to reach Adegbile, who currently works for Vermont Senator Patrick Leahy, but was unsuccessful.