But he did nothing wrong anywayThere is no need to wait for a charge. As soon as a crime has been committed (or, I'd argue, as soon as an action has been taken that a person could potentially be prosecuted, rightly or wrongly, over), a pardon can be issued.
Yeah, I think we could use a fair amount more willingness to prosecute high level politicians. Some people worry about going too far in the witch hunt direction but I think most nationally famous politicians can scrounge up good representation one way or another.