Ben Yagoda spotted a nice case of overnegation on NPR's "Morning Edition" earlier today, when Renee Montagne interviewed political science professor Michael McDonald about early voting. After explaining that Obama was leading in early voting in Nevada, McDonald said, "I don't want to discourage people from not voting today."
Here's the audio and my transcript (NPR transcript here):
McDonald: And those, um
those votes are breaking, um, heavily, uh, in favor of Obama
ah, and the polling shows a lead for Obama in the state
so, it would be very unusual for Mitt Romney to somehow
um, come from behind to win Nevada.
But still, you know, it's possible…
McDonald: …and I don't want to discourage people from not voting today.
This particular misnegation crops up here and there online:
This is one way to intimidate and discourage people from not voting. (link)
Perhaps requiring a legitimate ID in order to vote may discourage many from not voting. (link)
so each of these counties, as well as counties in other crucial swing states is to frighten those undecideds with xenophobic, jingoistic race baiting or discourage those undecideds from not voting. (link)
He said such a campaign was intended to create fears and panic among aliens, aimed to discourage people from not voting for the NPP. (link)
Of course, not every case of "discourage X from not voting" is a misnegation. Take this example from MSNBC's Chris Matthews, talking with Brian Williams about Iraqi elections in 2005:
Was it that clean? Was there no pushing by American soldiers or coalition forces to make people vote or discourage them from not voting? Was it a clean turnout, in other words? (link)
McDonald likely intended to say either "I don't want to discourage people from voting," or "I want to discourage people from not voting," but ended up with one negative too many. As with so many misnegations, it's easy to see how it transpired.