ELI5: Why has the Warsaw Pact dissolved, yet not NATO?  The Warsaw Pact, along with the USSR, is historically known to have dissolved in the year of 1991. NATO, equivalent alliance to the Warsaw Pact, continued well beyond this date; expanding and strengthening to this very day.  

 Why is this? European security is already insured by the European Union's self defense treaty, so common sense would allude to NATO being nothing more than a tax drain on both European and North American economies. 

 Could we ever see NATO dissolve, with the European Union continuing to carry the torch on? 