Leading congressional Democrats and 46 state attorneys general are urging President Clinton to veto a Republican plan to reorganize the Department of Energy.

The reorganization, prompted by China's alleged theft of U.S. nuclear secrets, would create a semiautonomous agency to oversee the DOE's enormous complex of laboratories and plants that research, assemble and maintain America's nuclear arsenal.

Congressional Republicans say the proposed National Nuclear Security Administration would tighten security and streamline the bureaucracy throughout the nuclear complex. Democratic critics say it would blur lines of authority and weaken environmental controls.

But the critics concede that because the reorganization has been inserted in the $289 billion defense authorization bill now before both houses of Congress for final passage, the only way to stop it may be a presidential veto--and the White House said yesterday that Clinton would wait for the bill to pass Congress before indicating what he would do.

A White House spokesman said Clinton wants a reorganization that "maximizes efficiency" and "does not negatively impact on future secretaries' ability to manage the department." But the spokesman did not say whether the bill as currently worded would meet those conditions.

Energy Secretary Bill Richardson already has expressed deep reservations about the GOP plan. Sen. Carl M. Levin (Mich.), the ranking Democrat on the Senate Armed Services Committee, took aim at the proposed reorganization yesterday, saying it would make the secretary of energy less accountable for security and counterintelligence.

To bolster his argument, Levin released an analysis by the Congressional Research Service that says the reorganization could "contribute to conflict" between the energy secretary and the administrator of the proposed nuclear agency, which would formally be part of the Energy Department but would have a substantial degree of autonomy.

Last week, 46 state attorneys general said in a letter to congressional leaders that the reorganization would undercut a 1992 law that explicitly gave the states regulatory control over the DOE's hazardous waste management and cleanup activities.

"Enhancing national security does not have to be inconsistent with protecting environment, safety and health," the attorneys general wrote. "But as set forth in [the reorganization plan], it is."

Rep. William M. "Mac" Thornberry (R-Tex.), who helped draft the reorganization plan in a House-Senate conference committee, said the attorneys general had been misinformed. He said the proposal would leave all existing state environmental controls in place.

Thornberry said the intent of the reorganization plan is to establish accountability and clear lines of authority within the nation's nuclear weapons program by insulating it from all of DOE's other activities, much as the Internal Revenue Service has semiautonomous status within the Treasury Department.

Thornberry called the contention that the energy secretary would lack control over the new nuclear weapons agency "ridiculous."

DOE officials, meanwhile, have spent days focused on a matter at Los Alamos National Laboratory, trying to determine how much sensitive nuclear information they would be willing to declassify to support criminal charges against Wen Ho Lee, a former physicist at the weapons lab identified as an espionage suspect and fired from his post in March for security violations.

While U.S. officials acknowledge that they lack evidence to charge Lee with espionage, the U.S. attorney in Albuquerque, John Kelly, is expected to decide within weeks whether to charge Lee with a felony for transferring nuclear weapons data from a classified computer network to his vulnerable desktop computer.

CAPTION: Sen. Carl M. Levin (D-Mich.) says the proposed reorganization would make the secretary of energy less accountable for security.