Peter Swire, Professor of Law at Ohio State, wrote an excellent piece of testimony for the Senate Committee on the Judiciary Subcommittee on the Constitution, Civil Rights & Property rights entitled “Laptop Searches and Other Violations of Privacy Faced by Americans Returning from Overseas Travel” (pdf). Basically, he makes an analogy between unrestricted laptop searches at the borders to when the US government tried to be a third party in all cryptographic communications. End result: it failed. Miserably.
He says, “Laptop searches will not succeed at a technical level at preventing data from entering or leaving the United States.” What this really means is: laptop searches at borders cannot possibly scale nor reliably produce any useful information for fighting crime.
At the end of the day, laptop searches and any unreasonable searches and seizures of any persons, houses, papers, and effects must be ruled illegal. Oh wait, we already have a constitutional amendment that guarantees just that:
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
People who actually know what they’re talking about will then say, “Border Search Exception! Border Search Exception! Border Search Exception!“
Yes, but even the border search exception requires “reasonable suspicion” to qualify. From “District Court Holds that Border Searches Require Reasonable Suspicion” by Eugene Volokh, a noted professor of law at UCLA (who also achieved a BS in Math and Computer Science at the age of 15, three years after he started working as a programmer:
Although neither a warrant nor probable cause is needed for ordinary searches of persons and things crossing the border, cause is required for more intrusive border searches. Certain border searches are highly intrusive because they implicate the "dignity and privacy interests of the persons being searched." Flores-Montano, 541 U.S. at 152. As a search becomes more intrusive, it must be justified by a correspondingly higher level of suspicion of wrongdoing. United States v. Aman, 624 F.2d 911, 912-13 (9th Cir.1980) (holding that to conduct a strip search, the authorities must have a "real suspicion" that the person is smuggling contraband and that "real suspicion" is "subjective suspicion supported by objective, articulable facts".
Swire also has a shorter article related to the testimony.