Strategists say that President Barack Obama's decision to scrap a controversial missile shield for Eastern Europe has mollified Russia, and could open the door for cooperation against common nuclear threats.
Russians are surprised, but largely welcoming of Obama's prize.
Moscow has long opposed a missile shield in Poland and the Czech Republic. But the US shouldn't expect too much in return.
High-level talks on contentious issues such as missile defense had a markedly different tone from past rhetoric.