Is the IRS reading your email? Maybe.
The American Civil Liberties Union (ACLU) recently obtained a copy of the IRS 2009 Search Warrant Handbook--a guide IRS agents use to determine whether they need to obtain a search warrant from a court to search a taxpayer's records, home, or business. The handbook says that "emails and other transmissions generally lose their reasonable expectation of privacy and thus their Fourth Amendment protection once they have been sent from an individual's computer." In other words, the IRS can read any email after it's sent.
The ACLU complained publicly that this policy violates the Fourth Amendment to the Constitution, which prohibits unreasonable searches and seizures by the government. The ACLU appears to be right. A Federal Appeals Court ruled in 2010 that Americans have a reasonable expectation of privacy in their email, and that government agents had to obtain a search warrant based on probable cause to require an Internet service provider (ISP) to turn over a person's emails. (U.S. v. Warshak, 631 F.3d 266 (6th Cir. 2010).)
A brouhaha erupted in the wake of the ACLU's disclosures. As a result, the IRS seems to have backed down. It released a statement that: "The IRS does not use emails to target taxpayers. Any suggestion to the contrary is wrong." However, neither the ACLU nor several members of Congress are satisfied with this short statement.
The Federal Electronic Communications Privacy Act, which was enacted in 1986, allows government agencies, including the IRS, to obtain personal emails without a warrant as long as they have already been opened or are older than 180 days. New legislation to change this rule is being considered in Congress.
Meanwhile, here's a good rule to follow: Never write anything in an email that you don't want the IRS (or any other government agency) to read.