Some Russian commentators and politicians rejoiced after Monday's meeting between the two leaders, with one columnist even calling it "another small miracle."
The U.S. and Russia still inspect each other's nuclear arsenals and have sharply curtailed the number of weapons poised to launch. That's thanks to two arms control treaties, which are now at risk.
Russia's president wants to normalize ties with the U.S., stop sanctions and give President Trump the impression he is the only Western leader who can get through to him.