Washington (CNN) -- Members of the U.S. Civil Rights Commission shouted at each other Friday over the Justice Department's decision to drop most of the charges in a 2008 incident in which black militants confronted voters at a Philadelphia, Pennsylvania, polling place, leading to charges of voter intimidation.
Conservative commission members accused the Justice Department of "stonewalling" the commission's investigation into the dismissal, and called a Justice Department's response to requests for information "breathtaking and insulting." A liberal commission member, in turn, dismissed those complaints as the "last gasps of a conservative majority of this commission."
At the end of the fractious hourlong debate, no minds appeared to be changed. But the commission, on a largely party line vote, decided to recommend that Congress give the commission more power when investigating Justice Department matters in the future.
The Election Day 2008 incident -- limited to one polling place in one city -- has grown in importance largely because of the testimony of J. Christian Adams, a Justice Department attorney who quit his job so he could testify before the commission. Adams testified the department had a hostile attitude about voting rights cases in which the victims were white.
No voters filed complaints in the Philadelphia incident, which took place in a majority black precinct. But some witnesses said they saw voters turn away from the polls, apparently in response to the two members of the New Black Panther Party, one of whom carried a nightstick.
Adams said the charges against the New Black Panther Party were dropped for political reasons, and alleged that an Obama administration appointee, Deputy Assistant Attorney General Julie Fernandes, had told others the department would pursue voting rights cases only in instances in which the victims were "traditional racial minorities."
"I was told by Voting Section management that cases are not going to be brought against black defendants for the benefit of white victims, that if somebody wanted to bring these cases it was up to the U.S. attorney, but the Civil Rights Division wasn't going to be bringing it," Adams testified in July.
Adams said another Justice Department attorney -- Christopher Coates -- could corroborate his testimony.
"If Mr. Coates were allowed to testify and tell the truth, then you would hear that these instructions were given."
But the Justice Department refused to allow Coates to testify, instead sending Thomas Perez, head of the department's Civil Rights Division, to testify. Perez testified the Civil Rights Division and Voting Rights Section operate in a color-blind manner, and that other factors -- including the evidence and resources -- influence departmental decisions.
"The department has responded to interrogatories and document requests it has received and has provided more than 4,000 pages of documents," Perez testified in May. He said the department had tried to be responsive while protecting "well-established and long-standing confidentiality interests" integral to its responsibilities.
In a letter this week to the commission, Perez again said the Justice Department's Civil Rights Division is "firmly committed to the evenhanded application of the law, without regard to the race of the victims or perpetrators." He does not believe Coates "is the appropriate witness to testify regarding current division policies," he said.
That drew a strong response from commission conservatives.
"They, by virtue of this letter, gave us the back of their hand," said commissioner Peter Kirsanow, a Republican. "This is contemptuous of this particular process," he said.
"All we're trying to do now is get a witness that can confirm or deny [that Fernandes ordered attorneys not to pursue voting rights cases only for traditional racial minorities]," said Commissioner Gail Heriot.
But others, including Republican member Abigail Thernstrom, who has sided with Democrats through much of the controversy, said it was ludicrous to believe that Fernandes had ordered attorneys not to pursue voting cases with white victims, saying anyone who would say that would be "a moron."
The contentious case goes back to November 4, 2008, when two members of the New Black Panther Party stood outside a polling station wearing paramilitary style uniforms and black combat boots. One of the individuals was armed with a nightstick. In the waning days of the Bush administration, the Justice Department filed a civil complaint against the men and their organization. Most of the charges were dropped by the Obama Justice Department, keeping a charge only against the man holding the nightstick.