Yes, but politically, "we dropped her sentence to seven years in jail" is more tenable than "we pardoned someone who never stood trial nor served a day in jail".
So don't pardon Snowden. Commute the charges against him. Like 97% of the cases that go to prosecution in this country, let him plea to a lesser crime and serve a 10 year sentence, minus time served in Russia.
Edit: Sorry, this was rubbish, I was thinking of Assange not Snowden.
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Note that charges (technically, a European Arrest Warrant in order to get him for questioning) against Snowden have not been made by the U.S. but by Sweden, for a suspected rape. So Obama definitely cannot commute them in any way.
There is no extradition request to the U.S., so when fighting an extradition to U.S., Snowden is beating a straw man.
It is not a prerequisite for a pardon, but it does serve the government's interests.
Pre-emptively pardoning Snowden before he spends a day in prison sends the signal that the government isn't going to punish people for leaking, so go right ahead.
Commuting Manning's sentence after seven years still leaves a pretty harsh warning for future leakers (is leaking that information worth seven years of your life?) while showing a degree of mercy to the individual (I mean, not the degree of mercy that commuting after 2 or 3 or 6 years would be...).
Regardless of what you think Obama's secret inner beliefs and motivations are, I think it is reasonable to assume that as Commander in Chief and President of the United States he wants the people he entrusts with secrets to keep keeping them.
