@Anonymous Coward - Non-proliferation treaty
Building mini-nukes does not violate the NNPT.
The US is still within the treaty - just. So far the US and the other declared nuclear powers have not abided by the Second Pillar of the NNPT to work towards final multilateral disarmament.
The US is arguably in violation of Articles I and II of the NNPT by continuing to deploy nuclear weapons in non-nuclear NATO countries and modifying these countries weapons systems to use nuclear weapons. There is also a question over the US's sharing of weapons designs and materials such as tritium with the UK and French weapons programmes. The UK may have violated it in the past by supplying the UK with plutonium diverted from our civilian reprocessing plant.
All of the original three signatories - the US, USSR (whose responsibilities were assumed by Russia) and UK have probably been in violation of public statements not to target non-nuclear states with nuclear weapons. The US certainly targeted North Korea, Russia has recently threatened to target Poland and the UK has said it will nuke anyone who uses WMD on British citizens. This is not a violation of the NNPT per-se as the statements were made outside of the treaty.
On another front the Bush administration has recently signed a civilian nuclear technology transfer with India which is not a signatory to the NNPT. It was agreed that India had not proliferated weapons knowledge and was in desperate need of nuclear energy so an exemption was made in the NNPT by the IAEA to allow the treaty to go through. IIRC it has still not been ratified by Congress, so it's possible the situation might change.