Data mining prompted fight over NSA domestic spying program

A 2004 dispute over the National Security Agency’s secret surveillance program that led top Justice Department officials to threaten resignation involved computer searches through massive electronic databases, according to current and former officials briefed on the program.

It is not known precisely why searching the databases, or data mining, raised such a furious legal debate. But such databases contain records of the phone calls and e-mail messages of millions of Americans, and their examination by the government would raise privacy issues.

The N.S.A.’s data mining has previously been reported. But the disclosure that concerns about it figured in the March 2004 debate helps to clarify the clash this week between Attorney General Alberto R. Gonzales and senators who accused him of misleading Congress and called for a perjury investigation.

The confrontation in 2004 led to a showdown in the hospital room of then Attorney General John Ashcroft, where Mr. Gonzales, the White House counsel at the time, and Andrew H. Card Jr., then the White House chief of staff, tried to get the ailing Mr. Ashcroft to reauthorize the N.S.A. program.