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President Obama has refused to accept the Russian purposal on shared control of the missile defence programme with US and NATO.
The US understands that it would be subject to Russian responsibility for protecting Nato from nuclear missile threat.
The US is offering Mascow a more limited role, in this regard, the US and Nato have agreed and proposed sharing in radar and in other early warning data.
Assistant US secretary of state Rose Gottemoeller a top US arm control negociator told that Obama has decided
“Nato will protect Nato and this is the bottom line as far as we are concerned”.
Hence, the raised issue could possible to break the deal.