It's very hard to see how this person or persons could be a whistleblower. They ought to be outed and they ought to be brought up on charges. Probably spying.
If this was France or Germany, and one of their secret-service people was found to be spying on the President or Chancellor....the guy would be arrested and hauled into a court with serious charges (well over 20 years).
With the Senate doing more or less nothing, it must now be considered OK for any intelligence guy to monitor a standing president (even a democrat).