A United Nations disarmament panel presented the first draft on Monday of a proposed global treaty to ban nuclear weapons, which advocates called an important step that could hasten completion of a final text by early July.

Nuclear powers including the United States have boycotted the negotiations for such a treaty, calling its goals naïve and unattainable — especially at a time when North Korea has threatened to launch nuclear-armed missiles at its enemies.

But those nations’ longstanding argument for deterrence — that the best way to keep nuclear arms from being used is to hold the ability to retaliate in kind — has failed to halt the momentum in the negotiations. The first round was held in March, and the effort is supported by more than 120 countries.

Treaty supporters have argued that if enough countries ratified an international agreement outlawing nuclear weapons, the political and moral coercive pressure would eventually persuade holdouts to reconsider.