Russia-US missile negotiations fail
Officials from both countries have been meeting in Budapest.
Russia is convinced the idea compromises its national security. They believe the shield's just too close for comfort.
For the U.S., Russian objections are a thorn in the side of plans for a truly global defence system.
The two delegations were led by Russia's Deputy Foreign Minister Sergey Kislyak and U.S. Assistant Secretary for International Security and Non-proliferation, John Rood.
All diplomats taking part in the talks said that it was a useful dialogue, which no doubt means more debate is ahead.
“My deep belief is that the negotiations we've been seeing over the last few months are a tactical game which doesn't actually open the strategic sense of this phenomenon,” said Vadim Kozyulin, Director of Conventional Arms, PIR Centre.
“The decision to deploy this southern defence system was taken not several months ago, but several decades ago, when the U.S. decided to develop the system and invest billions of dollars,” he added.