There are limits, it seems, to the detente Secretary of State Madeleine K. Albright forged two years ago with Senate Foreign Relations Committee Chairman Jesse Helms (R-N.C.), and the administration crossed one of them June 1.

That was Helms's deadline for the Clinton administration to submit for Senate ratification modifications negotiated with Russia to the 1972 Antiballistic Missile Treaty. Helms believes the amendments would fail to receive the two-thirds vote required for ratification, an outcome that in his view would scuttle the entire ABM treaty, which he and other congressional conservatives have long sought to abandon.

The administration is required by law to submit the amendments, but for political and strategic reasons is not prepared to do so now. So it ignored the deadline. Helms is trying to force the issue.

His staff has drafted legislative language to make future treaty ratifications -- not just on arms control but on any issue of Helms's choosing -- conditional upon submission of the ABM amendments. The language, which Helms as committee chairman has the power to attach to any future ratification measure, would prohibit the White House from putting any new treaty into effect until the ABM amendments go to the Senate.

Helms could simply prevent new treaties from coming up for ratification votes, but doing that would enable the administration to depict him as an irresponsible obstructionist, congressional staff aides and administration officials said. By moving treaties through but attaching the limiting language on implementation, he shifts the burden to the White House.

Helms had served notice on the administration that he would not move toward ratification of the Comprehensive Test Ban Treaty -- the showpiece of President Clinton's arms control policy -- until the ABM amendments have been considered.

"It's amazing how much power a chairman can wield," said Joseph Cirincione, chairman of the Nonproliferation Project at the Carnegie Endowment for International Peace. "The outcome of a vote would be very time-sensitive. It depends on what's happening internationally. If Helms were to force it today, I think the treaty would lose" because of Russia's unauthorized troop deployment in Kosovo, new threats from North Korea and the Chinese nuclear espionage scandal.

The Cold War may have ended, but the intense debates about nuclear arms control that it spawned have not. As China's military power grows and countries such as North Korea and Iran develop missiles that can strike far beyond their borders, the Clinton administration has sought to address these threats by amending and extending agreements that originated in the Soviet era, while defense hawks in Congress want to expand U.S. defenses against threats that they believe cannot be warded off by words on paper.

The proposed amendments to the ABM treaty form the arena where much of this struggle is taking place.

The treaty essentially bars the construction of defense systems that could intercept or shoot down intercontinental ballistic missiles. The theory was that neither the United States nor the Soviet Union would begin a nuclear attack if it was unable to defend itself against the retaliatory barrage of nuclear missiles that would surely ensue. The treaty prohibits mobile and sea-based defense systems and limits each side to one fixed site with no more than 100 interceptors.

Since the pact was signed, two developments that no one foresaw at the time have created the need to amend the treaty. One was the breakup of the Soviet Union. One set of pending amendments would make the treaty multilateral by bringing in Belarus, Kazakhstan and Ukraine, former Soviet republics that gave up nuclear weapons when they became independent.

The other development was the proliferation of shorter-range "theater" missiles, such as Iraq's SCUDS, which do not threaten the U.S. mainland but could reach U.S. or allied troops in the field in the Middle East or South Korea. The second set of ABM amendments would define the difference between strategic or intercontinental missiles, against which defenses are prohibited, and theater missiles, which are not covered.

Helms has argued that the ABM treaty expired when the Soviet Union did. The treaty partner having ceased to exist, the pact has no more force than a treaty with the Ottoman Empire, in his view. Administration officials say Russia is a valid successor party to the Soviet Union and the dozens of treaties it signed.

Helms denounced "the Clinton administration's stubborn adherence to the antiquated and defunct ABM treaty" as the biggest obstacle to development of a national missile defense system.

Several other Republican senators, such as Jon Kyl (Ariz.) and Thad Cochran (Miss.), share Helms's disdain for the treaty while not necessarily endorsing his tactics. They have argued that the pact unnecessarily limits U.S. options in developing both theater and national missile defense systems, which they see as increasingly needed to defend against the new threats.

Helms has not surfaced his treaty-limiting language publicly, and the administration has not indicated how it would respond. Under language putting a separate arms control treaty into effect, the administration is required to submit the ABM amendments for Senate action, but a senior official said it will not do so until the Russian parliament ratifies the START II nuclear arms reduction treaty.

The parliament has persistently balked at doing that, but a senior administration official expressed hope that the impasse could be nearing an end. "Every indication we have is that with Kosovo behind us, the Russians are prepared to work the problem," he said. "We'd like to send [the amendments] up in connection with positive movement by the Russians on strategic reduction."