President Obama has cancelled a planned pow-wow with Russian president Vladimir Putin at next month's G20 Summit in St Petersburg, saying the granting of asylum to NSA whistleblower Edward Snowden was "a factor."

"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," the White House said in a statement.

"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."

The statement also listed missile defense and arms control, trade and commercial relations, and global security issues as factors in the decision. Russia's policy on "human rights and civil society," (presumably a reference to the legalized gay-bashing that has become common in the former USSR) was also cited.

Affairs of state will still continue of course – the planned meeting between US Secretary of State John Kerry, Secretary of Defense Chuck Hagel, and their Russian counterparts will go ahead on Friday in Washington as planned. But the move is a very public bit of arm-twisting by the White House, which is odd considering that it makes Obama two-for-two in broken promises on the subject of Snowden.

During a June trip to Africa with his immediate predecessor, George Bush, the subject of Snowden came up in a press conference and Obama dismissed the issue as just another extradition case of a "29 year-old hacker." The US wouldn’t be scrambling aircraft to force down planes or engaging in diplomatic shenanigans over Snowden, he said.

"I get why it's a fascinating story from a press perspective. And I'm sure there will be a made-for-TV movie somewhere down the line. But in terms of US interests, the damage was done with respect to the initial leaks," he said.

Just six days later, the jet of Bolivian president Evo Morales was forced to land in Vienna and was searched after reports that Snowden was on board. While no jets were actually scrambled, France, Spain, Italy, and Portugal denied the aircraft access to their airspace, leaving it with little choice but to submit to a search.

Now, six weeks later, it is diplomatic fencing time, with the president cancelling his planned meeting with Putin over the issue. One wonders quite how far the US is willing to go to get its hands on Snowden, and how worried those in power are about what unreleased documents he still has.

Given that the leaks so far detail the mass surveillance of world data traffic (and of US citizens), the routine lying of security agencies about their remit and motives, the complicity of the world's largest technology firms in aiding and abetting this surveillance, and the extent to which "national security" spying data is fed back to local law enforcement, then Snowden's remaining revelations must be quite something indeed. ®