Broadly, a whistle blower reports apparent or suspected wrong doing in an approved manner to an agency of government, usually for disinterested reasons, while a leaker provides information to the news media or someone else unapproved for the information in order to gain an advantage or promote a cause of one sort or another.
Since Cantor is a House leader, he is part of the Congressional oversight process and his informant was therefore a whistle blower, with Cantor then doing the correct thing and asking the FBI why Congress had not been informed of the Petraeus matter.
In practice though, going to the news media is often less risky than trusting government, and many frustrated whistle blowers end up sourcing stories for the new media.
The distinction is one of motives and to whom the information is directed.
Broadly, a whistle blower reports apparent or suspected wrong doing in an approved manner to an agency of government, usually for disinterested reasons, while a leaker provides information to the news media or someone else unapproved for the information in order to gain an advantage or promote a cause of one sort or another.
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Thank you for your reasoned response. What you say makes sense. Guess I’m just too quick to draw conclusions about leakers/whistle blowers. But going to the right person w/ information makes sense. I’m not sure in this case why Cantor needed to know about an affair...but then I’m not sure we know everything there is to know about this incident...yet.