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After the Supreme Court’s DNA decision, what is the future of criminal justice?

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Technological innovation, from photography to fingerprinting, has long made identifying suspects easier for law enforcement. DNA testing is no more than the latest development in that progression, according to a decision by the Supreme Court on Monday.

As The Post’s Robert Barnes reports, the Court’s decision will allow police to continue what has become a routine in many states: using cheek swabs to take DNA from the people they arrest.

“Law enforcement agencies routinely have used scientific advancements in their standard procedures for the identification of arrestees,” Justice Anthony Kennedy wrote for the majority.

DNA testing has led to the exoneration of more than 300 people wrongly convicted of crimes. Yet the technology is far from fulfilling its promise of aiding law enforcement to identify criminals and letting the innocent go free. A Department of Justice study estimated that around 900,000 requests for biological screening, mostly DNA testing, were backlogged nationally at the end of 2009, the most recent year for which data is available. Meanwhile, large numbers of kits from routine arrests may be making the problem worse, argued Brandon Garrett, a professor at University of Virginia School of Law.

“As taking more DNA from arrestees has increased, the backlogs have increased at the expense of testing DNA from actual crime scenes,” he said.

Garrett also said that simply adding a DNA sample from everyone who is arrested might even make it harder for police to identify criminals, increasing the likelihood of false positives without adding any perpetrators to the system.

“A lot of innocent people will have their DNA in these databases,” he said. “That dilutes the databases and weakens their power.” He argued that since many criminals have prior convictions, taking samples only from convicts would be more efficient. The state’s constitutional authority to take samples from convicts is not disputed.

Barry Scheck, one of the directors of the Innocence Project, agreed. The organization helps wrongfully convicted people clear their names through DNA analysis.

“We’re all in favor of DNA databanks, and using them to exonerate the innocent and apprehend the guilty,” he said. Scheck and two coauthors wrote a book on the subject, and Kennedy quoted them on the value of DNA testing in his opinion.

But Scheck, who disagrees with the ruling, said he worried the court’s reasoning could open the way for large numbers of minor offenders’ DNA profiles to be pointlessly added to databases.

“What’s most important is that when you have an unsolved crime, within 7-10 days of the commission of that crime, it [DNA evidence] should be uploaded to the forensic database,” he said.

In a friend-of-the-court brief he filed with Erin Murphy of New York University School of Law, UVA’s Garrett argued that for these reasons, the government’s interest in acquiring DNA from arrestees is not strong enough to outweigh their protection under the Fourth Amendment.

The court disagreed, but states are still free to decide whether they’ll use the authority that Monday’s decision secured for them. The ruling is not the end of the discussion about how DNA testing can make law enforcement fairer and more effective.