Treaty on the non-proliferation of nuclear weapons
Signed at Washington, London, and Moscow July 1, 1968
Ratification advised by U.S. Senate March 13, 1969
Ratified by U.S. President November 24, 1969
U.S. ratification deposited at Washington, London, and Moscow March 5, 1970
Proclaimed by U.S. President March 5, 1970
Entered into force March 5, 1970
... Article VI
Each of the Parties to the Treaty undertakes to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a Treaty on general and complete disarmament under strict and effective international control ...
http://www.fas.org/nuke/control/npt/text/npt2.htm The failure of the existing nuclear-weapon states to disarm has been a continuing irritation to the non-nuclear-weapon states, as indicated (for example) by this 2004 interview:
Balancing Nonproliferation and Disarmament: An Interview With Brazilian Ambassador and NPT Review Conference President Sérgio de Queiroz Duarte
... ACT: Brazil is a member of the New Agenda Coalition, which contends there has not been meaningful action by the nuclear-weapon states toward fulfilling their disarmament obligations under Article VI. How can the nuclear-weapon states live up to these commitments, and how important is it that they are perceived as doing so?
Duarte: It is very important that they are perceived to be living up to their commitments. I think it's a question of confidence, a question of transparency and of improving the climate of mistrust that exists
. If the measures the nuclear-weapon parties took for nuclear disarmament were perhaps better understood by the remainder of the countries and were accompanied by very clear gestures of a continued commitment to arrive at that end-a reaffirmation which could be done at the Review Conference-it would help a lot to allay some of the mistrust that exists. It is something that each of the nuclear-weapon states-parties must do on its own. I do not have any reason to doubt the seriousness of any of the parties, nuclear or non-nuclear. If they are seriously committed to some steps, they should continue to be committed and fulfill their obligations, but they must do it in a way that will convince the rest of the parties that they are really complying. It is a difficult thing to do ...
ACT: Several countries spoke out strongly at the last PrepCom that any exploration of new nuclear weapons by the nuclear-weapon states violates the spirit of the NPT and is at odds with the 13 steps on disarmament. The treaty contains no prohibition against the research or development of new nuclear weapons by the nuclear-weapon states, and in fact they built thousands of additional nuclear weapons following the NPT's conclusion in 1968. Why should the nuclear-weapon states refrain now from any research or development into new nuclear weapons when most of their arsenals are steadily decreasing?
Duarte: Research is one thing, but production is another. The fact that there is research adds to a climate of less-than-complete confidence among the parties. It would be useful if the nuclear-weapon states refrained from doing anything that would be perceived as continued reliance on nuclear weapons ...
http://www.armscontrol.org/interviews/20041104_Duarte.asp In fact, Brazil for a while spoke openly of leaving the NPT if the nuclear-weapon states did not make meaningful progress towards disarmament. John Bolton ensured that the conference, referenced in the above interview, accomplished almost nothing -- yet another piece in the Bush Administration attack on international agreements.
I can't see any reason to think that such unhappiness on the part of the non-nuclear-weapon NPT signatory states is unreasonable ...