Nation states instead have interests, and may choose in their own interest to invest in whatever they want, including nukes, and do so weighing the costs and benefits and risks.
It makes sense for middle-sized nations, who might be able to afford nuke programs, but at considerable expense, to voluntarily surrender their "right" to build nukes, in a situation where there is verifiable and widespread agreement by other nations to do the same.
The mid-sized nation might accept the threat or protection of a super power (like the United States or Soviet Union), in exchange for agreeing to not build its own nuke program.
Comparing the nation state to the human individual by analogy is almost always poor analysis.
Treating the United States with moral equivalence to other nations is a sign of ignorance. (Well, before the election of Obama it was.)
This sums it up well:
KPS GILL
Quotes
Democracy and liberalism are not a sufficient defence and this is a fact that the ideologues of freedom need, equally, to comprehend. There is a fatal flaw in the liberal mind. Having established, in structure and form [though seldom in substance], a system of governance that corresponds to its conception of democracy, it feels that nothing more needs to be done. The Truths of the liberal ideology are, as the American Declaration on the Rights of Man expresses it, Self Evident. They require no proof, no reiteration, and no defence - certainly no defence by force of arms. Once democracy [or even the ritual of quinquinneal elections] is established, according to liberal mythology, the mystical invisible hand keeps everything in place; the superior wisdom of the masses ensures order and justice.... This is just so much rubbish. As we should know after living with falsehoods for fifty years now. Truth does not triumph; unless it has champions to propound it, unless it has armies to defend it.
From his book, Punjab: The Knights of Falsehood
http://en.wikipedia.org/wiki/Kanwar_Pal_Singh_Gill
Kanwar Pal Singh Gill, was born in Ludhiana, Punjab, India. He began his career as a police officer in the north-eastern state of Assam, quickly earning a reputation as a tough officer. He became a household name across the country as Punjab police chief in the early 1990s, when he was credited with crushing a separatist revolt in the Sikh-majority state.
Widely given credit for addressing the terrorism in Punjab, Mr. Gill was dubbed Super Cop after his success in Punjab. He publishes the Faultlines journal and runs the Institute for Conflict Management, as well as advising governments and institutions on security related issues. He was asked by the government of Sri Lanka last year for similar advice. Mr. Gill has also written a book, The Knights of Falsehood, which explores the abuse of religious institutions by the politics of freedom struggle in Punjab.
He got involved in sports administration after retirement and is currently the IHF (The Indian Hockey Federation) president.
He has also been appointed as a consultant by the Chattisgarh government to help tackle the Naxalite movement in the state.
Mr. Gill is a well known authority on counter terrorism advising governments and institutions on wide ranging security and counter insurgency issues. His analysis and views on the topic can be accessed at www.satp.org
Criticism
For some critics his success is a part of the story started by predecessor Julio Francis Ribeiro who started the Bullet for Bullet campaign of hitting back at militants and the strong hand in dealing with militancy adopted by Chief minister Beant Singh.