Debo Adegbile in  2013. (Evan Vucci/AP)

Senate Republicans are vowing to continue their vocal opposition to President Obama’s nomination of Debo Adegbile to head the Department of Justice’s Civil Rights Division, expressing outrage over the fact that he once served as a legal representative for an internationally known convicted cop-killer.

Adegbile, 47, spent more than a decade working for the NAACP’s Legal Defense Fund and served as the group’s in-house voting rights expert. In was in that role that Adegbile contributed to appeals filed on behalf of Mumia Abu-Jamal, who was convicted of the 1981 murder of  Philadelphia police Sgt. Daniel Faulkner.

Asked about his participation in Abu-Jamal's appeals during the Senate Judiciary Committee hearings on his nomination in January, Adegbile insisted that, despite Abu-Jamal's conviction, he deserved legal representation during his appeals.

"It was about the legal process and it was years after the conviction," he told the committee. "It's important, I think, to understand that in no way does that legal representation, zealously as an advocate, cast any aspersion or look past the grievous loss of Sergeant Faulkner."

But that explanation has failed to sway Republican lawmakers. Sen. Pat Toomey (R-Pa.), one of the most ardent opponents of Adegbile’s nomination, appeared alongside Rep. Mike Fitzpatrick (R-Pa.) on Monday morning at a Philadelphia news conference attended by almost  200 police and law enforcement officials, according to aides. There, he vowed to continue vocally opposing Adegbile's nomination.

"Anybody that would choose to come to the aide and participate in this gross miscarriage of justice, that's just not a good candidate to run the civil rights division of the Department of Justice," Toomey said during a local radio interview prior to the news conference. "As far as I know, there is no Republican support for him."

The nomination, which made its way out of the Senate Judiciary Committee last week, is expected to come up for a vote of the full chamber some time in the coming weeks, and the body — barring a massive coup in the Democratic caucus — is expected to approve the nomination.  

Abu-Jamal’s case became an internationally recognized political lightning rod, and many civil rights groups have alleged that he did not receive a fair trial for the murder of Faulkner, 25, a white officer.

Abu-Jamal, a former black panther and radio journalist, was initially sentenced to death for the murder. He has continued to maintain his innocence and, in 2001, a judge rescinded his death sentence, which was eventually replaced with a sentence of life in prison without parole. For the next decade, Abu-Jamal continued to appeal both his conviction and his sentence, during which time Adegbile – working for the NAACP Legal Defense Fund – assisted in his legal representation.

In 2009, Adegbile was one of several lawyers who assisted in the filing of several court briefs that alleged that Abu-Jamal’s conviction was handed down by a discriminatory jury and that appealed for this charges to be tossed. Adegbile's defenders stress that was not his direct choice whether the NAACP legal fund worked on Abu-Jamal's behalf and that a judge ultimately found that the appeal -- which claimed jurors were given improper instructions -- had merit.

Adegbile's nomination, which was approved Thursday by the Senate Judiciary Committee by a 10 to 8 party-line vote, has also drawn criticism from the Fraternal Order of Police, which declared that his confirmation would be a “thumb in the eye of our nation’s law enforcement officers,” as well as several other national law enforcement groups.

In a lengthy statement released last week, Sen. Chuck Grassley (R-Iowa) explained that, while he believes Adegbile to be a man of integrity, he could not bring himself to look past his participation in several cases during his time working for the NAACP – including his decision to assist in the representation of Abu-Jamal.

“Mr. Abu-Jamal is this country’s most notorious cop-killer,” Grassley wrote in the statement he issued with his “no” vote during the Senate Judiciary Committee’s consideration of the nomination. 

But while some on the right continue their outrage at the nomination, several prominent Democrats have voiced their support for the nomination, which – barring defections by Democratic senators – is expected to pass the full chamber.

“Debo is careful, he listens, and he understands the importance of building consensus,” said Sen. Patrick J. Leahy (D-Vt.), who leads the Judiciary Committee, after its approval of the nomination. “Anyone who knows him understands that he is a man of the utmost integrity.”

In letters to the Senate Judiciary Committee, civil rights activist and current Rep. John Lewis (D- Ga.) voiced his “unwavering support” for the nomination, while Rep. Marcia Fudge (D-Ohio), chairwoman of the Congressional Black Caucus, declared that Adegbile would bring “precisely the type of experience, professionalism and leadership skills necessary to run the [Civil Rights Division].”