What's missing in the government's briefs in the Playpen warrant cases

As regular readers know, dozens of federal district courts around the country have ruled on motions to suppress evidence in cases arising from the Playpen warrant. The cases all involve the use of government-installed malware to search the computers of visitors to a child pornography website and to reveal the users' true Internet protocol addresses.

In earlier posts, I have expressed strong disagreement with an argument some district courts have adopted that obtaining a user's Internet protocol address by accessing the user's computer is not a Fourth Amendment "search." (If you missed those posts, start here.) Although the government didn't press this argument in every case, some government briefs did make the argument and some trial judges adopted it. I disagreed, calling the argument "clearly wrong."

The first Playpen cases have been briefed on appeal to the circuit courts, and I thought it worth noting that the government appears to have dropped this argument on appeal. Just looking through Westlaw's CTA-BRIEFS database, which contains many (but not all) circuit court briefs, I see three Justice Department merits briefs filed in Playpen cases: United States v. Levin in the 1st Circuit, filed Oct. 31, 2016; United States v. Horton in the 8th Circuit, filed Nov. 22, 2016; and United States v. Workman in the 10th Circuit, filed Dec. 28, 2016.

Notably, none of the briefs disputes that use of the malware was a "search." The only reference to the question in the government's briefs appears in a footnote in the Horton reply brief, filed Jan. 9, 2017:

In claiming that he was prejudiced, Horton argues (at 12-14) that he had a reasonable expectation of privacy in his IP address and the information stored on his computer, but we have not suggested otherwise.

It was wise for the government to drop that argument, I think, for the reasons offered in my earlier post.