Labor Secretary nominee Thomas Perez testifies on Capitol Hill on April 18. (Molly Riley/AP)

Republicans and Democrats sparred again on Tuesday over President Obama’s nominee for labor secretary, Thomas Perez.

The setting was a House hearing on the assistant attorney general’s handling of a whistleblower case, but the session included his use of personal e-mail for official business and fervent finger-pointing over each party’s political motivations.

The contentious joint hearing, which involved members of the House oversight and judiciary committees, came one day before a Senate committee is expected to vote on whether to confirm Perez, who heads the Justice Department’s civil rights division.

The vote had been set for April 25, but Senate Democrats postponed it until after the House hearing.

The civil rights division under Perez’s leadership agreed not to assist in a whistleblower complaint against the city of St. Paul, Minn., in exchange for the municipality dropping its Supreme Court challenge against certain housing-discrimination guidelines, according to House oversight investigators who questioned Perez about the deal.

Key House and Senate Republicans said in an April report that the Justice Department’s failure to intervene in the Minnesota whistleblower case resulted in a missed opportunity to recover up to $200 million in taxpayer funds awarded through “false certifications.”

GOP lawmakers have suggested Perez made the deal for ideological reasons — to keep the Supreme Court from weighing in on the legality of housing-discrimination protections.

Perez has denied personal involvement with the decision not to sue St. Paul, telling lawmakers at a Senate confirmation hearing in April that lower-level Justice Department lawyers made the decision.

Shelly R. Slade, a former Justice lawyer who specialized in cases involving fraud against the government, testified Tuesday that she would have recommended declining the whistleblower case, partly on the grounds that it was not winnable.

Slade said she agrees with Justice’s decision to consider wider national interests beyond the St. Paul case.

“I see nothing the least bit untoward or unusual about that action,” she said in her written testimony. “The civil division’s decisions on intervention often take into account another agency’s broader policy concerns or interests outside the four corners of the case.”

The St. Paul whistleblower, pastor and builder Frederick Newell, said after testifying that he feels caught in the middle of two fights — Perez’s confirmation and a potential battle over discrimination guidelines — unrelated to his immediate concerns about St. Paul housing issues.

“It’s been difficult to address the issues I want to address in this political climate,” Newell said, noting that his goal is to ensure that cities comply with federal rules for disbursing HUD funds.

During the hearing, lawmakers spent nearly as much time trading barbs and bickering over procedural rules as they did questioning witnesses. Democrats said the hearing was politically motivated, while Republicans insisted Perez had done a disservice to taxpayers.

“Most alarming about this quid pro quo is the precedent that this case sets for future whistleblowers who bring claims of waste, fraud and abuse, only to be thrown under the bus for political purposes,” said Rep. Jim Jordan (R-Ohio).

Rep. Jerrold Nadler (N.Y), ranking Democrat on the Judiciary Committee, argued that “the entire purpose of this hearing is to attack the leadership and reputation of one of this nation’s best public servants.”

Republicans also suggested that Perez had violated the Federal Records Act by using his personal e-mail account for Justice Department business, including communications with a lawyer representing St. Paul and a tip to a New York Times reporter about the department’s 2011 settlement over claims of unfair loans by Bank of America’s Countrywide Financial unit.

The Justice Department said in a letter to Rep. Darrell Issa (R-
Calif.), chairman of the House oversight committee, that Perez used his personal e-mail account “to allow him to review or edit documents after normal working hours.”

Issa sent a letter to Perez on Monday accusing him of ignoring an April 10 subpoena because the department refused to hand over additional personal e-mails. Justice has said the e-mails are publicly accessible as part of on-the-record communications with Justice. “Your continued and blatant disregard for a duly issued congressional subpoena is extremely disconcerting,” Issa said.

The Justice Department has “made extraordinary efforts” to accommodate the committee’s requests, saying in a letter last week that it had already provided more than 1,400 pages of documents and all relevant personal e-mails.