Legally, the 100-mile-wide region is called the "extended border" of the U.S., as
defined by Title 8 of the Federal Code of Regulations. There is also something called the "functional equivalent" border, which is the area around international airports in the interior region of the U.S.
The DHS ruling from last Friday said its "warrantless searches" applied to the U.S. "border and its functional equivalent," with no mention of the extended 100-mile border.
Two
analysis papers from the Congressional Research Service from 2009 offer some legal insight into what tactics agents can follow within the 100-mile-wide extended border, and why the distinction between the extended border and the other two borders is important.
Searches within the 100-mile extended border zone, and outside of the immediate border-stop location, must meet three criteria: a person must have recently crossed a border; an agent should know that the object of a search hasn't changed; and that "reasonable suspicion" of a criminal activity must exist, says the CRS. (The service had done the legal analyses to prepare Congress members for legislation.)
"Although a search at the border's functional equivalent and an extended border search require similar elements, the extended border search entails a potentially greater intrusion on a legitimate expectation of privacy. Thus, an extended border search always requires a showing of 'reasonable suspicion' of criminal activity, while a search at the functional equivalent of the border may not require any degree of suspicion whatsoever," the CRS says.
The fact that agents need to show "reasonable suspicion" outside direct border stops and airports
puts their actions closer to the scope of the Fourth Amendment, says the CRS.
"The Fourth Amendment mandates that a search or seizure conducted by a government agent must be 'reasonable.' As a general rule, courts have construed Fourth Amendment
reasonableness as requiring probable cause and a judicially granted warrant. Nonetheless, the Supreme Court has recognized several exceptions to these requirements, one of which is the border search exception."
The argument about a Constitution-free zone may better apply to direct border stops and airports, where agents don't need to explain why they are searching a computer or cell phone. So, there could still be a "Constitution-free zone," based on the outcome of legal appeals. It would just be much smaller than that 100-mile band around the U.S..
The CRS says the Supreme Court has yet to consider a case involving the degree of suspicion needed to search laptops at the border without a warrant or reasonable suspicion.