Rep. Darrell Issa pressed ahead with a committee vote Wednesday to hold Attorney General Eric Holder in contempt of Congress, despite an 11th-hour move by President Obama to exert executive privilege over the Fast and Furious documents at the heart of the dispute.

The announcement touched off a caustic debate on the House Oversight and Government Reform Committee that lasted into the afternoon, as Democrats accused Issa of prosecuting a "political witch hunt" and Republicans stepped up their criticism of Holder's "stonewalling" over the Fast and Furious probe. Even for Washington, the tone at the hearing was decidedly bitter and accusatory.

The House Oversight and Government Reform Committee was first informed of the president's decision to exert executive privilege in a letter Wednesday morning, shortly before the contempt vote was scheduled...