News this week of the traumatic death of 25-year-old Freddie Gray of Baltimore at the hands of police is both dismal and emotionally bruising.

Mr. Gray, whose biggest crime in life was perhaps being a “joker,” as close friends reported, was nabbed by police after he looked them in the eye and ran. Sometime between being wrestled to the sidewalk, handcuffed and dragged into a police van and being taken unconscious by ambulance to a hospital 30 minutes later, his spinal column was nearly severed and his larynx crushed.

Even with surgery, he languished in a hospital for seven days before he died.

For his family’s sake, we hope he had a morphine drip.

It is difficult to decide how to deal with this — whether another march will change the chain of violence perpetrated upon citizens by the very people who are sworn to protect them.

What will it take to stop the abuse and end the killing?

How can the steadily eroding trust in police be restored?

The U.S. Supreme Court offered a sliver of hope Tuesday in its ruling that serves to return a bit of power to the people.

The ruling, Rodriguez v. United States, blocks police from turning a routine traffic stop into an unreasonable and unlawful search and seizure.

The person at the heart of the case is Dennys Rodriguez, who was stopped by police after he swerved his SUV on a Nebraska road. He told police he swerved to avoid a pothole.

After checking Mr. Rodriguez’s license, registration and proof of insurance, the officer started writing a warning citation. However, he also walked his drug-sniffing dog around the vehicle despite Mr. Rodriguez’s refusal to the officer’s initial request.

The dog signaled the presence of drugs. Police searched the SUV and found a bag of methamphetamine.

Mr. Rodriguez eventually pleaded guilty to a charge of possession, but later appealed on the grounds that the evidence was gathered illegally.

The U.S. Supreme Court ruled 6-3 that the U.S. Constitution’s protections against unreasonable search and seizure prevent police from extending an otherwise completed traffic stop to allow for a drug-sniffing dog to arrive.

“We hold that a police stop exceeding the time needed to handle the matter for which the stop was made violates the Constitution’s shield against unreasonable seizures,” Justice Ruth Bader Ginsburg wrote.

Traffic stops and other routine interactions with police can turn violent and deadly, as we have witnessed time and again. But the high court’s ruling helps us to take heart and to take control back.

We must understand the law, understand our rights and stand tall in the Constitution that was designed to protect us.