The Loophole That Lets Cops Stop, Question and Search You for No Good Reason

OFF THE WIRE
By Simon Davis-Cohen
Cops are using roadside traffic stops to throw the Fourth Amendment out the window.
Checkpoints occupy a unique position in the American justice system. At these roadside stations, where police question drivers in search of the inebriated or “illegal," anyone can be stopped and questioned, regardless of probable cause, violating the Fourth Amendment’s protection against “general warrants” that do not specify the who/what/where/why of a search or seizure. Though the Supreme Court agrees that checkpoints skirt the Fourth Amendment, the Court has been clear that the “special needs” checkpoints serve, like traffic safety and immigration enforcement, trump the “slight” intrusions on motorists’ rights.
We have checkpoints for bicycle safety, gathering witnesses, drug trafficking, “illegal” immigration and traffic safety. Many states, like California, require cops to abide by “neutral” mathematical formulas when choosing which drivers to pull over (like 1 in every 10 cars). In reality, these decisions are left to the discretion of individual police officers, which results in a type of vehicular stop and frisk.
That’s why people in Arizona have sued the Department of Homeland Security for its wanton deployment of immigration checkpoints in their state. Among their complaints are racial profiling, harassment, assault and unwarranted interrogation, and detention not related to the express “special need” of determining peoples’ immigration status.
A key legal detail about checkpoints is that they cannot be used for crime control, as that would require individualized probable cause. But legal scholars argue that non-criminally-minded checkpoints are also illegal. They point out that the Fourth Amendment protected the colonists from being searched for non-criminal “wrongdoing.” Doing nothing wrong at all, they argue, is not grounds to be searched or have your property seized. 
Regardless, unlike DUI checkpoints, these immigration checkpoints, expanded by the 2006 Secure Fence Act, are only allowed within 100 miles of the continental United States’ border. But that’s a big perimeter. Nine of the country’s 10 largest cities, entire states and some two thirds of the US population reside within this constitutionally exempt zone.
At these checkpoints—some of which have become permanent fixtures on the highway—people are forced to stop when flagged down, again regardless of probable cause. But the extent to which people are legally obliged to answer officers’ questions is unclear and seemingly arbitrary. Not surprisingly, the military's immigration checkpoints have garnered outspoken criticism from across the political spectrum. Legalized by the Supreme Court in 1976, these checkpoints seem to have taken on a new momentum in the post-9/11 era. (Private militias have even taken to setting up their own versions.)
DUI checkpoints, on the other hand,  deemed constitutional in 1990, monitor roadways in 38 states. But they have been outlawed by 12 others that have invoked states’ rights to increase federal civil liberty protections. In the Court’s 1990 opinion, Chief Justice William Rehnquist wrote that states’ interest in eradicating drunk driving is undisputable and that this “interest” outweighed “the measure of the intrusion on motorists stopped briefly at sobriety checkpoints,” which he described as “slight.”
In the dissent, William Brennan reminded the Court that, “some level of individualized suspicion is a core component of the protection the Fourth Amendment provides against arbitrary government action.” In pulling people over at random, checkpoints remove this individualized component.

Today, the practice seems to be experiencing a renaissance of sorts. With the help of local police, private government contractors have used the tactic to collect anonymous breath, saliva and blood ( DNA) samples of American motorists for the federally funded National Roadside Survey of Alcohol and Drugged Driving. Participation in the survey is voluntary, despite the confusion that may come with uniformed police asking for bodily fluids. Motorists are offered $10 for cheek swabs and $50 for blood samples. These practices have sparked considerable public outrage; law enforcement officials in St. Louis, Missouri and Fort Worth, Texas have stated their intent to limit their future participation in the study.