WASHINGTON - Missile defense, an issue that has poisoned US-Russia relations, could be a "game-changer" that transforms ties if the two sides cooperate on a shared system, says a report by former top officials from both sides of the Atlantic.Recent headlines in both countries have been reminiscent of the Cold War, with the Russians threatening to deploy missiles aimed at countering a proposed US missile shield, and the Americans responding that they will build the system, come what may.The planned US shield, endorsed by NATO, would deploy US interceptor missiles in and around Europe in what Washington says is a layered protection against missiles that could be fired by countries like Iran.Moscow says this could undermine its security if it becomes capable of neutralizing Russia's nuclear deterrent.Now an international commission that has been working on the matter for two years has designed a basic concept for cooperation with the help of military professionals from both sides.The new proposal by the Euro-Atlantic Security Commission says the United States, NATO and Russia could share data from radars and satellites about missile attacks and so provide one another with a more complete picture of any attack than countries would have on their own.But the parties would remain responsible for shooting down any missiles that threaten them. They would keep sovereign command-and-control over their own missile interceptors."While the Russians are somewhat skeptical about whether Iran is a threat ... the Russians are very strident about their worries about Pakistan, which has ballistic missiles and nuclear weapons," said Stephen Hadley, a co-chairman of the working group that produced the proposal. He served as national security adviser to former President George W. Bush, a Republican.The head of NATO welcomed the proposal."Overall I really think it points in the right direction," said NATO Secretary-General Anders Fogh Rasmussen at a security conference in Munich. "It outlines why it is in our common interest to develop cooperation on missile defense."However, he added, one of the main obstacles to cooperation was the Russian insistence on having legal guarantees that the NATO system was not directed against Russia. If Russia was involved in the project might alleviate Moscow's anxiety over the system, he said."The very best guarantee Russia could get would be to actually engage in positive cooperation because that would provide transparency and they could see that the system is not directed against Russia," he said.Russian Foreign Minister Sergei Lavrov, speaking at the same conference, did not refer to the commission's proposal, and instead threatened to "compensate" if necessary for the missile defense system."If our concerns are not taken into account, if no equitable joint work is achieved, then we will have to compensate for the emerging imbalance," he said in a speech."Failure to agree would tremendously reduce the opportunities for cooperation in addressing not only missile risks, but the whole range of threats to our common security. That would not be our choice."Hadley said a working group of experts from the United States, Europe and Russia concluded that there was enough of a threat from the proliferation of nuclear weapons capabilities and ballistic missiles with a range of up to 4,500 km (2,800 miles), to conclude that defenses were needed."Constructing defenses takes a long time, and the last thing you want to be - if you are doing defenses - is late to the party," he told Reuters in an interview.Hadley co-chaired the missile defense group together with Volker Ruehe, a former defense minister of Germany, and Vyacheslav Trubnikov, a former Russian deputy foreign minister and retired general.The design of the shared system was created by Henry "Trey" Obering, a former chief of the US Missile Defense Agency, and Viktor Esin, a former chief of staff of the Russian Strategic Rocket Forces.The missile defense proposal was part of a larger report by the Euro-Atlantic Security Commission that said the United States, NATO countries and Russia should cooperate on the Arctic, energy issues, and regional conflicts as well as missile defense. It is being unveiled this weekend at an annual international security conference in Germany."Successful cooperation on ballistic missile defense would be a game changer," the proposal said. "It would go a long way toward overcoming the legacy of historical suspicion and achieving the strategic transformation that is needed.""Cooperation on missile defense would establish a pattern for working together, build trust, and encourage further cooperation in other areas," it said.