( CNN ) -- North Korea 's apparent cooperation with nations seeking to end its nuclear weapons ambitions -- six years after a deal collapsed and two years after testing a bomb -- may lead to questions about why it would play ball now . Some signs show North Korean leader Kim Jong Il does intend to drop his nuclear weapon program , experts say . One school of thought : The communist nation , in desperate economic straits , has long been willing to drop its program for better relations with the United States . But mistakes on both sides interfered , according to Jim Walsh , a national security analyst . North Korea could be trying to achieve survival through deceit , intending to keep its nuclear weapons as blackmail for better treatment , analysts suggest . But those making a case for North Korea 's sincerity , Walsh said , would say it must `` do the things economically that [ it needs ] to do to avoid collapse . '' `` Having nuclear weapons when the regime is collapsing wo n't do them much good , '' said Walsh , a research associate at the Massachusetts Institute of Technology . North Korea , following a 2007 agreement with five nations including the U.S. , handed over a declaration of its nuclear program on Thursday . The nation also took steps to disable a reactor that officials acknowledge helped extract plutonium to build nuclear weapons . On Friday , it destroyed the reactor 's cooling tower -- significant because the tower would take a year or longer to rebuild . Watch the tower being demolished . » . After North Korea 's declaration , President Bush said Thursday that he intends to move North Korea from the U.S. list of states that sponsor terrorism . Down the line , North Korea would receive economic and energy assistance if the U.S. and other nations agree it is complying with other efforts to dismantle its nuclear program . North Korea has been heavily sanctioned in the past because of its nuclear program . Stephen Hadley , the U.S. national security adviser , told reporters Thursday that the terror list was one incentive for North Korea to drop its nuclear ambitions . `` I think it is important to them not to be on a list that says 'enemies ' and not to be on a list that says 'supporters of terror , ' '' Hadley said . Walsh said North Korea has been weakened by sanctions and its lack of arable land , leading to a population unable to feed itself . `` It ca n't grow enough food , '' Walsh said . `` And they 've got to attract foreign investors . '' He said North Korea was better off in the days of the Soviet Union , when it had an ample amount of communist nations with which to trade . But the Soviet Union collapsed , and many other nations turned away from communism , leaving North Korea increasingly isolated . `` Geostrategically , North Korea was growing weaker , and everyone around them was growing stronger , '' Walsh said . In 1994 , North Korea pledged to the U.S. that it would freeze and eventually dismantle its nuclear program in exchange for international aid , including help building two power-producing nuclear reactors . By 2000 , however , North Korea was complaining that not all the aid was coming as promised . In 2002 , the U.S. accused North Korea of working on a secret nuclear weapons program , and the U.S. said North Korea admitted doing so . Countries including the U.S. halted oil supplies , and North Korea withdrew from the Nuclear Nonproliferation Treaty . It conducted an underground test of a nuclear weapon in 2006 . Walsh said both sides have n't fully lived up to previous agreements . The U.S. , he said , promised normalized trade at one point but did n't follow through . Jon Wolfsthal , senior fellow of the Center for Strategic and International Studies ' international security program , said North Korea has been `` remarkably consistent '' regarding its reactions to U.S. positions . `` When we 've engaged them directly , they have responded . And when we have reduced our commitment , to our engagement ... they have responded negatively , '' Wolfsthal said . Wolfsthal said China -- which provides oil and food aid to North Korea -- has been instrumental in getting North Korea to cooperate . `` China has gone from being an uninvested ... mediator to being a true participant in this process -- from a country that originally wanted to help the U.S. and North Korea work out their differences to a state that has worked to convince North Korea to meet its obligations , '' Wolfsthal said . Wolfsthal said he believes China was embarrassed by North Korea 's nuclear test , and shifted course . `` I think that over time , the United States has helped China see that North Korea 's unpredictable behavior destabilizes their own backyard , '' he said . Walsh and Wolfsthal said another theory has it that North Korea is only playing with negotiators and intends to keep its nuclear program and weapons as a security blanket . Expanding on that possibility , Wolfsthal said North Korea leader Kim Jong Il could keep the country 's nuclear arsenal but agree not to produce any more nuclear weapons . `` Everybody 's speculating . None of us has met Kim Jong Il , '' Wolfsthal said . Walsh said the West does n't have hard evidence to determine North Korea 's intentions . `` But so far , the evidence is pretty strongly on the side of North Korea wanting a real bargain , '' Walsh said .
North Korea 's negotiations driven by economic need , desire for survival , experts say . China , embarrassed by nuclear test , has prodded North Korea , expert says . Deceit possible , experts say , but nation 's best interest is to be on West 's good side .