Efforts by US Secretary of State John Kerry to persuade his Russian colleague Sergei Lavrov that the two nations must cooperate in stopping the war in Syria were billed as the last chance to halt a deterioration in relations between the two old Cold War adversaries.
But Mr Kerry's gambit has failed, and US diplomats have stopped talking. Citing the "radically changed environment", Russian President Vladimir Putin has retaliated by suspending a landmark nuclear agreement.
One of US President Barack Obama's top pledges upon assuming office was a "reset" in relations with Russia. He even presented Moscow with a giant computer button bearing that word in Russian. Unfortunately, the word was misspelt, and so was the policy. For, what Mr Obama offered - cooperation in halting global crises, nuclear disarmament - Mr Putin found unimpressive, while what the Russian leader wanted - a recognition of Russia's spheres of influence - the United States never contemplated.
Relations between the two are now at their lowest ebb since the 1980s. And they are unlikely to improve any time soon. Moscow is beefing up its security services, unifying them under one security super-ministry. The last time this was done was in the 1930s, at the height of the Stalinist rule in the Soviet Union. Meanwhile, Western nations are deploying troops to the former communist countries in Eastern Europe, which feel threatened by this Russian development.
The heightened tension means big trouble in the Middle East, where Russian troops are digging in, largely to challenge US dominance of the region. It also means further tensions in Europe, where Ukraine continues to burn. And it draws Russia closer to China, another big power which resents US policies.
US-Russian relations will be one of the most difficult challenges facing the next US president.