Looking at each:

1. The reported NSA leaks tipped off the Russians about how to avoid surveillance.

A caveat up front: It's very difficult for anyone without security clearance to analyze the Snowden leaks and determine what they might have revealed to the Russians. Perhaps they used Facebook exclusively for communicating between Putin and the front lines, meaning that PRISM was picking everything up. Lay people (and, probably, non-Russians) don't know what channels were used.

Most of the Snowden revelations outline on intelligence-gathering focused on individual actors. Which makes sense: the expansion of NSA powers under the Bush and Obama administrations was meant to improve the country's ability to uproot terrorists, who operate in small cells or as individuals more frequently than they act under the aegis of a country. Details about how the NSA surveilled social media networks or observed unencrypted communications between corporate servers show how the agency targeted people who lack their own private communications networks. This is why Americans are angry and worried; they, like terrorists, use corporate infrastructure to communicate.

Revelations about how the NSA taps international network centers also seems an unlikely culprit for allowing the Russians to evade detection. Would missives from the Kremlin to army units near the Ukrainian border route through England? Moreover: Would the NSA's observing those connection points really come as a surprise to the Russians? There are other specifics that Snowden revealed, such as tapping world leaders' phones and surveilling communications at diplomatic events — neither of which occurred within the window of action in Crimea.

Perhaps the most likely report that could be blamed for tipping off the Russians are of the NSA's efforts to undermine online encryption. The NSA worked to build holes into standard encryptions systems. If the Russians weren't using customized peer-to-peer tools to encrypt communications between the Kremlin and the military — which would be a massive failure on their part — it's possible that the NSA revelations changed their behavior.

All of these seem unlikely.

2. Snowden — intentionally or not — gave the Russians more information than is public.

Theory A: He gave them information intentionally. One of the longstanding arguments about Snowden has been that he is a spy for, first, China, and then Russia. He's repeatedly indicated that he isn't a spy, but, of course, that is what a spy would say.

The idea that Snowden is a spy is perhaps the strongest argument for Snowden's having provided the Russians with information that allowed them to evade detection. No one — including the NSA — is entirely certain what documents he stole. Some might contain information of great interest to foreign actors.