If Snowden had left the Moscow airport and gone to Venezuela or some other country, I don't think Obama would have canceled the summit with Putin.

But Obama has to show our intel people that he has their backs and this is the most demonstrable way he can prove that.

The Hill:

President Obama has canceled a meeting in Moscow next month with Russian President Vladimir Putin to protest that country's decision to give Edward Snowden temporary asylum. 

Obama still plans to attend the Group of 20 summit in St. Petersburg but will not sit down for a previously scheduled meeting with Putin in Moscow. 

"Following a careful review begun in July, we have reached the conclusion that there is not enough recent progress in our bilateral agenda with Russia to hold a U.S.-Russia Summit in early September," White House press secretary Jay Carney said in a statement on Wednesday. 

"Russia's disappointing decision to grant Edward Snowden temporary asylum was also a factor that we considered in assessing the current state of our bilateral relationship," he added.

Carney said Russia had been informed about the schedule change and that U.S. officials would continue to work with their Russian counterparts on a host of issues. 

"Our cooperation on these issues remains a priority for the United States, so on Friday, August 9, Secretaries Hagel and Kerry will meet with their Russian counterparts in a 2+2 format in Washington to discuss how we can best make progress moving forward on the full range of issues in our bilateral relationship."

National Security Adviser Ben Rhodes said it was the unanimous opinion of Obama's national security team that the president should skip the meeting with Putin.

"We'll still work with Russia on issues where we can find common ground, but it was the unanimous view of the president and his national security team that a summit did not make sense in the current environment," Rhodes said in an interview with the AP.

Snowden still might end up in Venezuela, at which point all will be forgiven and Obama and Putin will be buddy-buddy again. There are too many issues of common concern for a breach to last very long.