Among Vladimir Putin's first acts now that he's back in Russia's top job was to cancel a date with President Barack Obama.

Both nations insist Putin's no-show at a high-profile economic gathering tailored for his attendance is not a snub. But the decision to skip next week's meeting of the Group of Eight industrial nations in the United States and a much-anticipated Oval Office meeting with Obama, may set a sour tone for the next four years.

If Obama wins re-election, he will have Putin as a sometime partner and sometime adversary through the end of his presidency. If Republican Mitt Romney wins, the dynamic might be very different. Romney has called Russia an "enemy," while Putin has signaled that he will hold off on any major new cooperation with the United States until he knows who will be president.

Either way, Russia watchers in and out of the U.S. government predict a more businesslike relationship than was the case under his predecessor, Dmitry Medvedev, and perhaps a more limited one.