"In each of these three cases, the system that was set up to detect any authorized access of these kinds of records worked. These unauthorized accesses were detected by the State Department and immediately acted on," said McCormack.

Undersecretary Pat Kennedy said some records have "what computer people call flags — we put flags on certain records that trigger a report to a supervisor that the record has been accessed," he said.

Not all 18 million passport records have flags, said Kennedy. The department's Bureau of Counsel Affairs determines what records to flag, he said.

Kennedy was less specific concerning what controls, if any, might restrict employees' or contractors' access to data once they've logged into the system.

The State Department's decision to provide broad access to passport records may seem, on the face of it, to be a problem. But the department is also trying to balance access to data with IT security, according to its IT Strategic Plan for 2006-2010 (PDF format). That plan points out that "one lesson of September 11, 2001, is that restricting access to information poses serious risks, often outweighing the impact of potential unauthorized disclosure."

The report goes on to say that "security decisions must be based on rigorous debate of pros and cons by all stakeholders: end-users, security specialists and IT experts."

The Obama campaign, which learned of the breach Thursday afternoon, is scheduled to be briefed by Kennedy on Friday. Responding to initial news of the breach, Bill Burton, an Obama campaign spokesman, said, "This is an outrageous breach of security and privacy, even from an administration that has shown little regard for either over the last eight years."

It is also unclear what investigative options are open to the department at this point. The inspector general -— actually, the acting inspector general; the position has been unfilled for several months —- can do little more than request interview time with the contractors' former employees.