Kenny Whetzel of Smithville was unpleasantly surprised this week when he opened his mailbox.

He found a letter from a group called Americans for Limited Government listing his name and address, along with the names and addresses of six of his neighbors.

It then listed whether he and some of his neighbors voted in 2004 and 2008 -- with a promise to update the list after Tuesday's election.

"We have conducted an audit of public voting records in your neighborhood, and wanted to present you with findings of past civic participation in your community," the letter said. "We will be updating our records ... then send an updated vote history audit to you and your neighbors with the results."

Voting records -- whether someone cast a ballot, but not who it was cast for --are public information. The letter violates no laws. But Whetzel, like some voters in other states getting similar letters, thinks the notice is a serious invasion of privacy.

And he doesn't care for the implied threat that his neighbors will be told if he doesn't vote this year.

"My reaction was, 'What the hell?'" he said. "If they can do this, what else can they do?"

Americans for Limited Government, based in Virginia, did not respond to several emails and phone messages seeking comment. In a statement quoted by other news organizations, a group spokesman said the mailer is intended only to encourage people to vote.

The letter-writing campaign appears national in scope, although it wasn't immediately clear how many letters were sent.

Political campaigns routinely use voter lists to reach out to the electorate, typically through mailed postcards and fliers.

"Candidates like to target frequent voters," said Dave Rinehart, Republican director for the Clay County Election Board. "That is public record, fortunately or unfortunately."

But the use of voter lists to expose voting habits is growing, because some political scientists now think peer pressure and embarrassment are strong motivators at election time.

You're more likely to vote, they say, if you think your neighbors will know whether you've cast a ballot.

This week, the Huffington Post reported the liberal group Moveon.org Civic Action planned to send 12 million similar voting history letters to voters in swing states. Voters' histories in those letters, however, will be compared to neighborhood voting averages rather than to any other specific person, the website said.

It isn't clear how many voter history letters have landed in the Kansas City area. Rinehart said he was unaware of any complaints in Clay County. Shelley McThomas, the Democratic director of the Kansas City Election Board, said she didn't know of any complaints about the letter.

In September, federal records show, Americans for Limited Government gave $1.95 million to a political committee called Now or Never PAC. In turn, Now or Never said this week it would purchase $1 million in advertising supporting U.S. Rep. Todd Akin's Senate campaign.

Americans for Limited Government's letter, though, does not mention Akin, opponent Sen. Claire McCaskill, or urge support of either major political party.

"Please be sure to continue your participation and exercise your right and responsibility to vote," it says.

Whetzel -- who said he voted in 2008, even though the letter says he didn't -- said he'll be sure and cast a ballot this year.

He's voting against anyone he believes Americans for Limited Government supports.

"I was going to split my vote," he said. "But it just had the opposite effect on me. I was mad and I said I'm not going to do it."