Judges have long wrestled with applying the Fourth Amendment’s protection against unreasonable search and seizure to modern technology, and one of the more interesting examples of this just happened in a Jan. 6 case.

The case, out of federal district court in Washington, involves “geofencing” warrants, which are used to identify people within a certain area and time range. Authorities use them when they believe a crime has been committed and want to identify the people who committed it. They’ve become a useful, if controversial, law enforcement tool that capitalizes on our reliance on smartphones. The government has used the technique to look for bank robbers, for example.

As NBC News’ Jon Schuppe reported this week, geofencing opponents have argued that these warrants violate the Constitution’s Fourth Amendment protections, even sweeping up innocent people in the process. Privacy advocates have raised concerns about these warrants being used to investigate abortions after the Supreme Court overturned Roe v. Wade last year.

In the case decided this week, the government got a geofence warrant for Google location data in and immediately around the Capitol from 2 p.m. to 6:30 p.m. ET on Jan. 6, 2021. David Rhine, charged with several crimes including disorderly conduct at the Capitol, was among those swept up in the probe and filed a motion to suppress. He argued that the warrant was overbroad and lacked particularity, defects that the Fourth Amendment was designed to protect against.

But Judge Rudolph Contreras of the U.S. District Court for the District of Columbia found the warrant constitutionally valid. Among other things in his 78-page opinion — read it here if you’re feeling adventurous — the judge noted that the geofence area “closely, although not perfectly, contours the Capitol building itself,” and that the area around the Capitol “is unusual for its lack of nearby commercial businesses or residences.”

So while geofencing — like all warrants and law enforcement moves — certainly merits scrutiny, the Jan. 6 warrant might not present the strongest challenge. As the judge noted,  

January 6 was a unique event in a geographically unusual place such that the scope of probable cause was uncommonly large. Because the Capitol building was not open to the public on January 6 due to the counting of the votes of the Electoral College, the fact of having entered the building during the geofence timeframe itself constitutes evidence of a crime.

I doubt this case is the last word on geofencing — whether in the Jan. 6 case or elsewhere. There’ve been relatively few court rulings on the subject and, again, this Jan. 6 ruling was only a trial-level decision. The validity of these warrants and how they’re used could become clearer on any appeals, which I’ll be monitoring on the blog.