After you read the excerpt from Slate magazine, read the entire article here.
Vote caging is an illegal trick to suppress minority voters (who tend to vote Democrat) by getting them knocked off the voter rolls if they fail to answer registered mail sent to homes they aren't living at (because they are, say, at college or at war). The Republican National Committee reportedly stopped the practice following a consent decree in a 1986 case. Google the term and you'll quickly arrive at the Wizard of Oz of caging, Greg Palast, investigative reporter and author of the wickedly funny Armed Madhouse: From Baghdad to New Orleans—Sordid Secrets and Strange Tales of a White House Gone Wild. Palast started reporting allegations of Republican vote caging for the BBC's Newsnight in 2004. He's been almost alone on the story since then. Palast contends, both in Armed Madhouse and widely through the liberal blogosphere, that vote caging, an illegal voter-suppression scheme, happened in Florida in 2004 this way:
The Bush-Cheney operatives sent hundreds of thousands of letters marked "Do not forward" to voters' homes. Letters returned ("caged") were used as evidence to block these voters' right to cast a ballot on grounds they were registered at phony addresses. Who were the evil fakers? Homeless men, students on vacation and—you got to love this—American soldiers. Oh yeah: most of them are Black voters.
Why weren't these African-American voters home when the Republican letters arrived? The homeless men were on park benches, the students were on vacation—and the soldiers were overseas.