WHEN IT COMES to the long-term storage of waste created during the manufacture of nuclear weapons, there are no easy solutions: These are materials that will remain radioactive for tens of thousands of years, and none of the scientific arguments about them are settled. For that reason, many were surprised last month to find that the Senate Armed Services Committee -- which doesn't usually make nuclear waste disposal rules -- has proposed to significantly change policy by inserting two paragraphs into the Defense Department authorization bill, after no testimony, no hearings and no public discussion.

If passed, these paragraphs could allow the Energy Department to clean up at least one site -- the underground nuclear waste storage tanks at the Savannah River facility in South Carolina -- "to the maximum extent practical," a standard that other legislators, notably Sen. Maria Cantwell (D-Wash.), say is vague and legally unprecedented. Both Ms. Cantwell and environmental groups say the department could, using this standard, cover a large quantity of radioactive sludge with concrete rather than removing the material -- an expensive but not impossible process -- for long-term storage at the Yucca Mountain site in Nevada. They also say that the standard would inevitably apply to Idaho and Washington, the two other states with underground storage tanks.

By contrast, Sen. Lindsey O. Graham (R-S.C.), author of the legislation, argues that the changes will expedite the long-delayed cleanup in South Carolina and give his state control over the process, without forcing Idaho or Washington to accept the same conditions. To prove his point, Mr. Graham has offered an amendment designed to prevent the Energy Department from "rewarding" South Carolina for its cooperation with extra funding, and he says he will support more explicit language if necessary. For her part, Ms. Cantwell has offered an amendment striking out the relevant paragraphs altogether.

At its heart, this argument -- which was acrimonious enough to stall the entire defense bill before the Memorial Day recess -- is about the lack of any national agreement about what "clean" means in the case of a nuclear waste site and about the absence of meaningful standards for the classification of nuclear waste. Everyone involved agrees that the federal government is ultimately responsible for disposing of the waste in these three sites. Nobody agrees on who determines when the disposal has been completed. But clearly, a situation in which states compete to reach private agreements with the Energy Department and then rush to put them into legislation is untenable. Congress should take this political spat as a sign that the previous rules still aren't working, determine clear jurisdiction and ensure that decisions are ultimately made according to the best scientific standards, not as the outcome of a political battle between states.