New documents from the Internal Revenue Service suggest the agency’s criminal tax division has been reading taxpayers' emails without a warrant despite an appeals court decision saying that violates the Fourth Amendment.

The 247 pages of documents were released to the American Civil Liberties Union after the ACLU filed a Freedom of Information Act request.

It is unclear how frequently the IRS obtains a search warrant. A 2010 decision by the Sixth Circuit Court of Appeals in the case United States v. Warshak found that the federal government must obtain a probable cause warrant before compelling email providers to turn over messages, Nathan Freed Wessler, a staff attorney with the ACLU noted in a blog post.

Prior to the Warshak decision, he said, it was IRS policy to read people’s email without obtaining a search warrant. The IRS took the position that the Fourth Amendment did not apply to email. A 2009 Search Warrant Handbook from the IRS criminal tax division’s Office of Chief Counsel claimed that “the Fourth Amendment does not protect communications held in electronic storage, such as email messages stored on a server, because internet users do not have a reasonable expectation of privacy in such communications.” The following year, a presentation by the IRS Office of Chief Counsel said that the “4th Amendment Does Not Protect Emails Stored on Server” and there is “No Privacy Expectation” in those emails.

The ACLU noted that older IRS documents show that the IRS often did not obtain warrants. For example, the 2009 edition of the Internal Revenue Manual explained that “the government may obtain the contents of electronic communication that has been in storage for more than 180 days” without a warrant.

After the Warshak decision, the IRS’s position did not appear to change. In an email exchange in mid-January 2011 on the subject of “U.S. v. Warshak,” an employee of the IRS Criminal Investigation unit asked two lawyers in the IRS Criminal Tax Division whether Warshak would have any effect on the IRS’s work. A Special Counsel in the Criminal Tax Division replied: “I have not heard anything related to this opinion. We have always taken the position that a warrant is necessary when retrieving e-mails that are less than 180 days old.”

In an indication that the IRS was considering the impact of the Warshak decision, an October 2011 IRS Chief Counsel Advice memorandum, which is available on the IRS Web site, an IRS employee asked for guidance about whether it was proper to use an administrative summons, instead of a warrant, to obtain emails that are more than 180 days old. The memo summarized the Warshak ruling and said that “as a practical matter it would not be sensible” to seek older emails without a warrant. However, the memo contended that Warshak applies only in the Sixth Circuit, but that, because the Internet Service Provider had informed the IRS that it did not intend to voluntarily comply with an administrative summons for emails, there was not “any reasonable possibility that the Service will be able to obtain the contents of this customer’s emails . . . without protracted litigation, if at all.”

“Any investigative leads contained in the emails would therefore be ‘stale’ by the time the litigation could be concluded, making attempted warrantless access not worthwhile,” Wessler wrote. “The memo misses another chance to declare that agents should obtain a warrant for emails because the Fourth Amendment requires it. Instead, the memo’s advice (which may not be used as precedent and is not binding in other IRS criminal investigations) is limited to situations in the Ninth Circuit where an ISP intends to challenge warrantless requests for emails. The IRS shouldn’t obey the Fourth Amendment only when it faces the inconvenience of protracted litigation; it should recognize that the Fourth Amendment requires warrants for the contents of emails at all times.”

Wessler noted that up to the present, the current version of the Internal Revenue Manual, also available on the IRS Web site, continues to explain that no warrant is needed for emails stored by an ISP for more than 180 days.

The IRS denied that it is reading taxpayer emails unlawfully. “Respecting taxpayer rights and taxpayer privacy are cornerstone principles for the IRS,” the IRS said in a statement. “Our job is to administer the nation’s tax laws, and we do so in a way that follows the law and treats taxpayers with respect. Contrary to some suggestions, the IRS does not use emails to target taxpayers. Any suggestion to the contrary is wrong."

However, the IRS has also provided guidance to investigators about reading puhlicly accessible social media sites such as Facebook to find out information about taxpayers that may contradict their tax returns, but investigators are not allowed to "friend" them (see IRS Uses Social Networks for Tax Probes). Three years ago, the Electronic Frontier Foundation released content from a 2009 IRS training course on using search engines and social networking sites, which the IRS had also provided in response to a Freedom of Information Act request.

On Thursday, House Ways and Means Oversight Subcommittee Chairman Charles Boustany Jr., M.D., R-La. wrote a letter to IRS Acting Commissioner Steve Miller asking about the IRS’s searches of taxpayer emails, text messages and social media to compile information without a warrant.

Boustany requested the IRS provide its privacy policies and procedures for when a search warrant is needed, including what information they are gathering and how frequently they search through emails and social media for taxpayer information.

"Recent media reports have disturbingly claimed that that it is the IRS's view that it does not need a search warrant to review certain communications by private citizens," Boustany wrote. "Other recent reports state that IRS officials have used social media, such as Facebook and Twitter, to mine additional information about taxpayers."

“Taxpayers deserve to know whether the IRS is violating their privacy,” Boustany said in a statement. “It is concerning that the IRS may be gathering information through Americans’ emails and social media and I demand to know what purpose it is serving.”