NPT 101: Which Countries Have Nuclear Weapons?

Beginning of article

The Non-Proliferation Treaty was designed to limit the acquisition of nuclear weapons to five countries who already had them. But now four more states have joined the nuclear club - an 'erosion' of the treaty that could spell its doom.

Five signatories to the Non-Proliferation Treaty, or NPT, have nuclear weapons: the US, Russia, China, France, and Britain. Of those, the US and Russia control the vast majority of the world's nuclear warheads.

Yet three non-NPT members - Israel, India, and Pakistan - have all secretly developed nukes and suffered little consequence. North Korea, a former signatory, took advantage of a loophole in the treaty, pulling out in 2003 and …