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.Read more here. http://www.salon.com/