One thing I don't understand - why would the US care? Why expend resources on trying to capture Snowden? He's basically harmless at this point - he's passed all the information he had to few journalists (which would be a better target now) and there's no way anyone will ever let him near anything more secret than grandma's cookies recipe. Besides petty vengeance, what's the point?
Four reasons off the top of my head: 1. There's no guarantee that he acted alone and or without outside sponsorship. 2. There's no guarantee that all the information that he took was released publicly. It would be helpful to know the extent of what was taken, and who else knows it. 3. It would be helpful to know what other intelligence services have asked him/taken from him. 4 "To encourage the others"
That has been debated and put to rest.
Our elected officials initially tried to say he was a Russian spy, but could not provide any evidence to support the claim.
If he were a foreign asset, like for the Russians, for example, he would not have acted the way he did. In fact, his handlers would have preferred that he continued to operate in secret and continue to feed them as much info as he can.