The Nuclear Non-Proliferation Treaty

The Nuclear Non-Proliferation Treaty (NPT) is a treaty regarding policies on nuclear weapons.  The word proliferation is defined as "rapid growth or increase in numbers"⁽¹⁾.  The treaty states that no country other than the 5 nuclear armed states (Russia, United States of America, United Kingdom, France and China) are allowed to possess nuclear arms.  It also says that they may not transfer their nuclear weapons, make more nuclear weapons or encourage others to make nuclear weapons.  As of now only 4 countries have not signed the NPT.  These countries are: Israel, Pakistan, India and North Korea which withdrew from the treaty in 2003.⁽²⁾⁽³⁾

I believe that if a country can simply back out of a treaty (as North Korea did) as soon as it stops being in its best interest, then it should have never signed the treaty to start off with.  The ability for countries to do that eliminates the whole point of having a treaty.