Within hours of the decision, U.S. Sen. Pat Toomey (R., Pa.), who has emerged as one of Adegbile's chief critics, began lobbying his colleagues to oppose the nomination.
Gov. Corbett and former Gov. Tom Ridge, both Republicans, added their voices Thursday to those opposing Adegbile - a coalition that includes District Attorney Seth Williams, a Democrat, and the Fraternal Order of Police.
"This nomination is an insult to the family and memory of Officer Daniel Faulkner," Corbett said in a statement. "I call on the Senate to take a long look at Mr. Adegbile's track record of radical positions in the legal arena and reject this nomination."
The vitriol remained outside Thursday's committee hearing. Inside, none of the eight senators who voted against his nomination voiced their concerns.
Sen. Patrick Leahy (D., Vt.), the committee's chairman, paused before the vote to defend Adegbile, who works as his senior counsel.
"Anyone who knows him knows he's a man of the utmost integrity," he said. "Criticism of his nomination has centered on just one case of the hundreds and hundreds he's been involved in."
Adegbile told the Judiciary Committee last month that while working for the NAACP's Legal Defense Fund in 2009, he supervised a team that represented Abu-Jamal before the U.S. Supreme Court.
Though he said he had no direct role in writing three briefs the NAACP filed with its appeal, he maintained that lawyers have a professional duty to protect the rights of even the most unpopular clients.
Conservatives and some police groups have maintained that Adegbile's ties to the case extended beyond mere professional duty.
Abu-Jamal had legal representation before the NAACP stepped in, and the organization's claims extended beyond whether his constitutional rights had been violated at trial, said Sen. Chuck Grassley (R., Iowa).
The briefs argued that instructions given to the jury were unclear and that racial discrimination played a role in the jury selection.
"So this isn't exactly a case of Mr. Adegbile . . . stepping in to defend an unpopular client who couldn't otherwise find a lawyer," said Grassley in a letter submitted to the committee. "This is not John Adams defending the British soldiers after the Boston Massacre."
Abu-Jamal spent nearly three decades on death row for Faulkner's murder before a federal judge overturned his sentence in 2009, citing unclear jury instructions.
The District Attorney's Office appealed the decision until the U.S. Supreme Court refused to overturn it in 2011. Prosecutors later decided not to resentence Abu-Jamal, effectively allowing him to remain in prison for life.
On Thursday, Adegbile remained quiet. He did not attend his confirmation hearing and spent the day meeting with various senators, including Pennsylvania's Robert P. Casey Jr.
Casey, a Democrat, has said he has not made up his mind on whether to support the nomination and wanted to meet with both Adegbile and the Fraternal Order of Police before deciding.