I believe one of the best moves Snowden could make right now is to demand a public trial, held according to American law, giving him a right to offer a full defense.
Not only would that make international headlines for months; which is exactly what the US doesn't want more of, publicity, but the evidence that would be presented at trial would be far more harmful to his accusers than it would be to Snowden.
The truths revealed by Edward Snowden hurt no honest person.
Those who do love liberty, truth, and a legal system that protects human rights from being trampled by despots, would welcome a public trial of Edward Snowden. Bring it!