Maryland v. King, now under review by the U.S. Supreme Court, is a landmark case described by Justice Samuel Alito as the most important criminal procedure case the high court has considered in decades. Hopefully, it will take its place next to the historic Miranda decision by establishing that the Constitution's Fourth Amendment protection against "unreasonable searches and seizures" extends to citizens' own DNA.

In 1994, the state of Maryland began to store genetic information from individuals convicted of rape and sexual assault. In 2002, the database was expanded to include DNA samples from all convicted felons. But in 2009, Maryland -- along with the federal government and 27 other states -- stepped over a line when it started collecting DNA samples from all arrestees, whether they had been convicted or not.

This is how Alonzo Jay King, a Salisbury man who was arrested in 2009 on misdemeanor assault charges, was linked to the 2003 rape and robbery of a 53-year-old Wicomico County woman, convicted and sentenced to life in prison.

King's attorneys in the Baltimore public defenders office appealed, arguing that taking DNA from arrestees without a warrant, now a common police practice, constitutes an unconstitutional seizure. Last April, Maryland's Court of Appeals agreed, throwing out King's rape conviction because the DNA sample was obtained after his arrest for an unrelated crime.

Appellate Judge Glenn Harrell Jr. said that since the police already had photographs and fingerprints confirming King's identity and enough evidence to convict him of the assault, the DNA sample was gratuitous. Noting that there may be "conceivable, albeit somewhat unlikely, scenarios" under which DNA samples can be legally obtained under the Maryland DNA Collection Act to identify arrestees, he added that the law cannot be used for "investigatory purposes."

During last Tuesday's hearing, Maryland Chief Deputy Attorney General Katherine Winfree told the Supreme Court justices that since 2009, Maryland has obtained 43 convictions under its warrantless DNA program. In 2011 alone, DNA samples were taken from more than 10,500 people arrested in the state, leading to nine convictions for unsolved crimes.

But Justice Antonin Scalia did not seem impressed. He noted that convictions obtained as a result of "unreasonable searches ... prove absolutely nothing." Since the police can arrest virtually anybody for a myriad minor offenses, warrantless DNA collection turns Marylanders' constitutional presumption of innocence on its head. That's too high a price to pay -- even for giving 43 criminals the punishment they deserve.