The North Atlantic Treaty Organization, a treaty between the most westenized of the European nations and the United States to maintain the balance of power with the Soviet Union and its Warsaw Pact "Allies" (ally with us or we'll roll tanks through your capital).  Now, NATO definetly accomplished its goal and war with the Soviets was averted, and eventually the USSR collapsed.  

So what is NATO up to these days?  Big things, let me tell you.  I remember reading about the NATO warplanes (mostly US warplanes) attacking armoured vehichles outside Sarejevo during the siege.  It was acclaimed as the first "combat" NATO forces actually engaged in.  What did they accomplish?  Not a lot.  The real decider in the Yugoslavian war was the importation of hundreds of weapons, including M60 MBTs and a cadre of men from groups like the MPRI to the Bosnian-Croat side in order to balance the power with the Serb forces.  Incidently, a few former general officers from the US military also helped out in the effort to finally defeat the Serbs.  

So now a reasonable balance of power is created, and then you have the KLA.  The KLA (Albanian Liberation Army) is (was) fighting the Serbs in Kosovo for their own independent nation in a war characterized by guerilla tactics and atrocities committed by Serb forces against Albanian civilians.  NATO decided to take a hand in the situation and "help" create peace.  So American troops entered into Kosovo and expelled Serb troops.  The balance of power shifted.  Suddenly, it was open season against Serb civilians, as there was no Army to protect them.  Now NATO troops turned to disarming the KLA.  Meanwhile, Serbians retaliated against Albanians and it escelated.  Who is the good guys?  A few months ago, US soldiers were involved in a firefight and shot some store owners who were in the middle of defending their store against armed guerillas trying to destroy their family's business.  Yeah, troops.  So now we have NATO troops following UN's example of creating situations where any reasonable expectation of peace depends on the troops presence.  Since the situation is destabilized, what happens when the troops pull out of Kosovo?  INSTANT CHAOS!  The troops there are basically holding up any semblance of peace by themselves, since they have effectively left everyone else defenseless.

Personally, with the fall of the Soviet Union, I feel that NATO is a worthless organization whose only purpose now is to maintain its existence.  Former Warsaw Pact countries have joined NATO!  What's next, Russia joining NATO?  Maybe China?  Look out guys, UN is not alone.