Did the Secret Service blow it when they let uninvited Tareq and Michaele Salahi into a state dinner or did the White House's social secretary, Desiree Rogers, leave them undermanned? At a hearing by the House Homeland Security Committee on Thursday, lawmakers grilled Secret Service director Mark Sullivan, who told them he believed the breach was an isolated incident "due just to poor judgement" by the agents in question. After Rep. Eleanor Holmes Norton (D- D.C.) suggested the Secret Service might have been understaffed given reports of increased threats against President Obama, Sullivan said that the president was in fact receiving a similar number of threats as former presidents Clinton and Bush. The White House declined to make Rogers available for the hearing despite criticism that she may have contributed to the breach by failing to post staffers with the Secret Service to go over guest lists while people entered. Committee chair Bennie Thompson (D-MS) said he would seek subpoenas for the Salahis, who were invited to the hearing and did not show, but not for Rogers, who he said was "not a central figure in this security matter." Rogers, a longtime close friend of the Obamas, previously worked as head of the Illinois Lottery and Peoples Gas, a utility company, before joining the White House.