Re: If your not on the list, you're not getting in
"Apart from the nuclear non-proliferation ones?"
There are no LAWS that prevent a country from building nuclear weapons if it wants to. They are not prohibited by the Geneva Convention, the Hague Convention or any other statutory conventions that we consider "international law".
Nuclear weapons development is restricted only by a TREATY - called the Non-Proliferation Treaty that is basically a "deal" where countries who sign up get to benefit from civilian nuclear technology from the P5 while they make a commitment not to develop nuclear weapons.
India didn't accept that "deal" and consequently was denied access to uranium, nuclear technology and other nuclear material so that it could build its nuclear weapons. North Korea, Iran and Iraq however did sign the deal (NK backed out later when "Lil Rocket Man" took over)