Washington (CNN) -- Political fireworks over a little-noticed Supreme Court appeal and a separate whistleblower lawsuit had U.S. Attorney General Eric Holder and a longtime congressional adversary exchanging harsh words at a House committee hearing Wednesday. Holder, testifying before the Republican-led House Judiciary Committee, sparred with GOP Rep. Darrell Issa of California over congressional requests for private e-mails of top Holder aide Thomas Perez, who is President Barack Obama's nominee to be Labor Secretary. Issa suggested Holder had political motives for delaying release of the electronic messages. The two repeatedly talked over each other, and Holder concluded the exchange with a personal attack.
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Attorney General Holder calls GOP Rep. Darrell Issa's conduct "shameful"
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Issa and Holder spar over emails involving aide Thomas Perez, a Cabinet nominee
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Issa led the effort to cite Holder for contempt of Congress last year in another case
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Holder answers questions by the House Judiciary Committee
However, Republican legislators had issued a subpoena for @placeholder's private e-mails, saying he may have used personal accounts to arrange the deal.