It is time to save an old friend. It is an age when acts of terrorism have produced irrational doubts about whether the laudatory principles our public documents espouse will serve, to some degree, as the prescription for our own undoing. These doubts are insidious, and have brought us closer to abandoning one of our democracy’s most vital principles—probable cause. Our fears about terrorism counsel that we indulge the urge to act expediently and, in such expedience, to compromise the probable cause doctrine in exchange for what we think would be greater collective security. Such an exchange devalues probable cause, as, in our fear, we overlook the fact that this is a zero sum game where we purchase security with the currency of personal freedom.
Probable cause is most assuredly becoming a victim of benign neglect. There is pressure to read it, and other provisions of the Fourth Amendment, as if they were penned in disappearing ink or contained a footnote that allowed for their suspension at the discretion of those elected to thwart the next terrorist attack. To the extent the probable cause doctrine may limit the government’s ability to deter future attacks, courts may consider not only neglecting it, but discarding it as nothing more than an historical eccentricity amenable to as many exceptions as the Fourth Amendment’s warrant requirement. But no matter how serious our fears, we cannot seem to bring ourselves to consign probable cause to history’s scrap heap. As political beings, our instinct holds us back because we sense that probable cause reflects something that goes to the core of our notion of what justice means in a free society. To abandon probable cause is to bring to an end a concept that has lasted many centuries and persevered through tumultuous times. A concept this old and resilient must speak to values quite profound. . . .