Senators Mike Lee (R-UT) and Ed Markey (D-MA) have sent another joint letter to Secretary of Homeland Security Kirstjen Nielson renewing their objections to requiring US citizens to submit to mug shots (“facial recognition”) as part of a DHS “biometric exit” program for identifying and tracking international travelers departing from US airports and seaports.

The letter sent last Friday is a follow-up to an earlier letter six months ago, in which the Senators told the DHS that such a requirement for US citizens is “facially unauthorized”:

Most crucially, while Congress has repeatedly voted to authorize biometric entry-exit scanning of foreign nationals, it has never authorized biometric exit screening for U.S. citizens. In fact, Congress has pointedly neglected to authorize DHS to use the program on U.S. citizens for any purpose. Additionally, while airport infrastructure may not be conducive to separate boarding procedures for U.S. citizens and non-citizens, convenience should not be placed above congressionally mandated requirements. We are concerned that the use of the program on U.S. citizens remains facially unauthorized.

The DHS reply to the Senators’ letter has not been made public. From the Senators’ follow-up letter, it appears that DHS officials tried to avoid the need to explain the legal basis (if any) for demanding mug shots of departing US citizens by claiming that citizens aren’t being required to submit to facial photography. As in their meeting with the Identity Project and other civil liberties organizations, earlier this year, it seems that the DHS told the Senators that US citizens can opt out out of having their photographs taken.

It hasn’t always worked that way, although anecdotal reports suggest that after we raised this issue with them, DHS officials may have sent a message to field offices and airports to allow US citizens to skip the “selfie” kiosks and proceed directly to CBP customs and immigration inspectors — if, but only if, they know that they can ask to opt out, and their request to opt out is actually honored. One US citizen told us they saved half an hour by skipping the line for the biometric entry kiosks.

The Senators, however,  are rightly unwilling to accept a “right” to opt out that is neither advertised nor explicitly recognized in DHS regulations.  They “urge” the DHS not to expand the biometric exit program without first completing a formal remaking (including notice of the proposed rules, and consideration of public comments on them) and promulgating regulations specifying explicitly how US citizens can opt out:

We request that DHS’ rule include specific details on the opt-out process for American citizens and the procedures that DHS would follow should an American choose to opt out.

The DHS is already collaborating with airlines and airports to collect and share photos of travelers for commercial and government tracking and surveillance purposes. Airlines are common carriers, so any requirement for airline passengers to submit to mug shots or provide photos or other biometric or personal information would have to be included in their published tariff to be enforceable. We don’t believe that an airline can lawfully require travelers to submit personal information as a condition of transportation. Any proposed tariff containing such a requirement should be disapproved by the US Department of Transportation as inconsistent with the airline’s obligation to operate as a common carrier and transport all eligible passengers willing to pay the fare in its tariff.

We are continuing to monitor what’s happening on the ground and how it may differ from DHS claims. We welcome reports, through comments in this blog or in confidential communications, from any US citizen who has been forced to forced to use a “selfie” kiosk or submit to a mug shot by DHS, airline, or airport staff or contractors as a condition of air travel or entry to, or exit from, the US.