The former Bush administration said a missile defence shield in Eastern Europe was vital to defending the continent from a potential attack from Iran and other "rogue states".
But the plan angered Russia who saw it as a threat.
Now the current US administration under Barack Obama, has made a u-turn, saying Iran’s long-range missile programme does not pose a threat, and has scrapped plans to base interceptor missiles in Poland and the Czech Republic - a move welcomed by Moscow.
But the US needs Russia's help in return.
Al Jazeera's Neave Barker reports from Moscow, the Russian capital.
Source: Al Jazeera