A frequently contentious U.S. Supreme Court is more accustomed to split decisions on the important issues of the moment (Citizens United, Affordable Care Act, etc.) than for resounding constitutional consensus.

But the court unanimously rose above ideological concerns Wednesday in a ringing affirmation of Americans’ right to constitutional protection from unreasonable searches, even when technology makes such intrusions easy.

Not only did the justices find an issue that transcends their own political differences, but they might have tapped into a common conviction and a core American value.

The short version of Wednesday’s ruling is that so-called “smart” cell phones are protected from warrantless searches. It’s an important decision from a court whose nominally conservative wing, despite conservatism’s commitment to limited government, has frequently leaned toward police in cases involving law enforcement’s search-and-seizure authority.

But given the amount of personal information accessible through Americans’ smartphones, these devices should be no more subject to warrantless searches than a private citizen’s DVD collection, library or family photo album.

“Cellphones differ in both a qualitative and quantitative sense from other objects that might be kept on an arrestee’s person,” Chief Justice John Roberts Jr. wrote. “… American adults who own a cellphone keep on their person a digital record of nearly every aspect of their lives, from the mundane to the intimate.”

As reported Thursday, the ruling was praised by observers as otherwise politically divergent as the liberal Constitutional Accountability Center and the libertarian Cato Institute — a spokesperson for the former hailing the decision as “a good day for the Bill of Rights” and one for the latter concluding that “being arrested for, say, not paying a speeding ticket will no longer open you up to having your entire life examined by law enforcement.”

In one very traditional sense, the court reaffirmed a long-standing legal precedent: Even the basic land-line telephones in common use for a century have generally required warrants for authorities to tap conversations. Given the amount of personal information stored in digital devices, the law’s protection of that realm of communication should be even stronger, not weaker.

“Modern cellphones are not just another technological convenience,” Roberts wrote. “With all they contain and all they may reveal, they hold for many Americans the privacies of life. The fact that technology now allows an individual to carry such information in his hand does not make the information any less worthy of the protection for which the Founders fought.”

That, finally, is the heart of the crucial legal principle at stake. The technological capacity to bypass the Constitution does not automatically confer authority, legal or ethical, to do so.