As Secretary of State Hillary Clinton exchanged accusations this past week with Russia over its alleged support for Syrian leader Bashar Assad, Obama's Republican opponent Mitt Romney released a terse statement declaring that the U.S. approach to Russian relations had "clearly failed." 

Romney cited Russia's support for Assad as well as its alleged protection of Iran from international sanctions. 

Russia, though, is still seen by some as key to resolving these standoffs. Russia has gone along with U.N. Security Council efforts to tighten some penalties against Iran over its nuclear program, though it has blocked the harshest punishments. 

The U.S. remains under pressure to tighten the screws on Iran this week, with or without robust Russian backing. 

Dozens of U.S. senators from both sides of the aisle penned a letter to the president Friday urging Obama to stand tough against Iran in the upcoming talks.