I’ve lately been immersed in what we might call the pre-history of the Fourth Amendment in colonial and British common-law and political thought, primarily by way of William Cuddihy’s magisterial treatise The Fourth Amendment: Origins and Original Meaning 602‑1791, as well as the exceptionally erudite work of Thomas Y. Davies. One thing that this review of Founding Era thought has driven home to me is how strange the main argument made by supporters of the FISA Amendments Act sounds in light of the Founders’ core concern with prohibiting “general warrants” and “writs of assistance,” which authorized broad and discretionary searches that were not confined to “particularly named” places or things.

At the very heart of the Fourth Amendment is the demand that government agents must not be authorized, by courts or legislatures, to conduct discretionary searches of the homes and papers of Americans, on a “fishing expedition” unmoored from specific evidence. A valid arrest warrant, for example, could not authorize police to emulate the king’s messengers in the infamous Wilkes Affair—who were empowered to enter any private home at their whim on the hunt for the authors and publishers of the radical weekly The North Briton. Unsurprisingly, given the historical abuse of search authorities to hound “seditious” writers, a consistent theme in Founding Era condemnations of the general warrant—that “worst instrument of arbitrary power, the most destructive of English liberty and the fundamental principles of law”—is a special horror at the prospect of agents reading through a citizen’s private papers and correspondence. This helps to explain why they are specifically (and perhaps somewhat redundantly) included in the phrase “persons, houses, papers, and effects” even though one would expect “papers” to be encompassed within the scope of “effects.” In the 21st century, our most sensitive “papers” are often made of bytes rather than wood pulp, but courts have generally understood them to be entitled to the same stringent protection.

Perversely, modern defenders of the FISA Amendments Act argue that sweeping NSA surveillance of our digital “papers” is constitutionally unproblematic precisely because it does not “target” the Americans whose papers are searched: The groups or individuals who are the “targets” of programmatic NSA communications interception must be foreign. One wonders what the Founders would have made of this strange “defense”: When the king’s messengers burst into printer Dryden Leach’s home in the dead of night to ransack his personal papers—acting on a secondhand report that John Wilkes had recently been seen in his shop—the fact that Wilkes and not Leach was the ultimate “target” of the search hardly excused it in the eyes of liberty-minded observers on either side of the Atlantic. What was so egregious was precisely that the messengers enjoyed “a discretionary power… to search wherever their suspicions may chance to fall,” and not merely a power limited to the person and property of their specific “target.”

Similarly, it’s not clear why the fact that the “target” of NSA’s information vacuum cleaner must be located overseas should comfort the thousands (if not tens or hundreds of thousands) of Americans whose private digital “papers” will be confiscated in the process. As the legislative history of FISA makes clear, the “target” in the context of that statute is simply “the individual or entity about whom or from whom information is sought. In most cases, this would be the person or entity at whom the surveillance is physically directed… but this is not necessarily so.” [Emphasis added.] In other words, surveillance that “targets” Al Qaeda is potentially surveillance of anyone talking about Al Qaeda, not necessarily to Al Qaeda.

Thus the law authorizes—one might even, ahem, say it provides general warrant for—the interception and storage of your confidential e‑mails, provided that NSA is looking for information about some foreign group or person, and provided they don’t know your e‑mail is entirely domestic at the time they intercept it. Of course, given how the Internet operates, there’s a decent chance you don’t know which of your own digital communications are entirely domestic either, unless you make a habit of running traceroute every time you send an e‑mail, visit a Web site, or chat over Skype or IM.

Perhaps because ordinary people aren’t clear on the precise meaning of “target” in the FISA statute—and because even those of us who pay close attention have to make educated guesses about just how NSA interception works—we’ve allowed legislators to get away with suggesting that the rights of Americans are adequately protected as long as Americans aren’t “targets.” Yet the governmental power our Founders regarded as most outrageous and tyrannical—the very paradigm of abuse that the Fourth Amendment was designed to protect us against—was just this kind of discretionary authority to inspect the private papers of citizens who were not specifically “targets” of a legitimate investigation. That’s why the Fourth Amendment protects us against unreasonable searches—not against unreasonable “targeting.”