The legislation (S. 1845) cleared the panel for the Senate floor on a 14-2 roll call.
Sen. Sheldon Whitehouse, D-R.I., said some 800 people in the executive branch have the ability to contact the Justice Department. Some 40 people in the Justice Department, he said, had permission to discuss matters with the White House.
"The greatest hazard to the independence of the Justice Department is the White House," said Whitehouse, a former U.S. attorney.
The bill would limit to four White House positions -- the president, vice president, counsel to the president and counselor to the president -- authorization for communication regarding an ongoing civil or criminal investigation. Those in the Justice Department allowed to discuss ongoing investigations with the White House would be limited to the attorney general, deputy attorney general and associate attorney general.
The bill would permit other communications between White House and Justice Department officials about non-investigative matters including policy, appointments, legislation, rulemaking, budgets, and intergovernmental relations.
The committee bill was a substitute by Whitehouse that requires semi-annual reports by the Justice Department and White House to the House and Senate Judiciary committees disclosing the names of those communicating about an ongoing investigation.
Senate Judiciary Chairman Patrick Leahy, D-Vt., said the Whitehouse bill was an important step toward repairing the damage that has been done to the Justice Department in recent years. He said that there had been a "dramatically expanded" number of persons permitted to communicate over investigations under former Attorney General Alberto Gonzales.
"We do not have to merely imagine the threat to the independence of law enforcement arising from those communications," Leahy said. "Our investigation revealed instances in which the department had been reduced to a political arm of the White House."