The Fourth Amendment guarantees Americans’ right “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures ...”

But according to a misguided ruling issued Monday by the U.S. Supreme Court, that right doesn’t include being secure from the police taking a sample of your DNA if you are arrested for a “serious crime.”

All 50 states already take DNA samples from convicted felons. However, by extending that reach to those who have not been convicted, the court has granted ominous new, Big Brother license to government.

And like much of the authorities’ widening use of modern technology to keep track of not just criminals but mere suspects, the decision undermines old-fashioned, limited-government concepts like the Fourth Amendment.

Thus, Monday’s 5-4 ruling on DNA samples rightly generated a heated — and compelling — dissent.

For years now, many 5-4 Supreme Court margins have featured four generally conservative jurists and their four generally liberal counterparts on opposite sides, with the decisive “swing vote” cast by Anthony Kennedy.

Yet this close call found Antonin Scalia, a strict constructionist who has repeatedly come down on the ideological right, joining in the minority with three justices who have repeatedly come down on the left: Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan.

Justice Scalia didn’t merely write the dissenting opinion. He read parts of it aloud from the bench to convey the intensity of his judicial objections. Among his pointed — and on-the-mark — observations:

■ “The court’s assertion that DNA is being taken, not to solve crimes, but to identify those in the state’s custody taxes the credulity of the credulous.”

■ “Solving unsolved crimes is a noble objective, but it occupies a lower place in the American pantheon of noble objectives than the protection of our people from suspicionless law-enforcement searches.”

Justice Scalia also fairly questioned which offenses will be deemed “serious” enough to force arrested suspects in those cases — again, not convicted criminals — to give DNA samples:

■ “Make no mistake about it: Because of today’s decision, your DNA can be taken and entered into a national database if you are ever arrested, rightly or wrongly, and for whatever reason.”

You need not be a conspiracy theorist to be troubled by government’s growing means of gathering information about you. Surveillance cameras proliferate, as does tracking of cyber communications — and even personal medical records.

Sure, law enforcement should have reasonable access to information that helps solve crimes. But that shouldn’t void our Fourth Amendment protection against unreasonable searches.

And while taking a DNA sample is a quick and physically painless process, it is far more intrusive — and revealing — than taking fingerprints.

As Justice Scalia concluded Monday, saving his best protests for last:

“It may be wise, as the court obviously believes, to make the Leviathan all-seeing, so that he may protect us all the better. But the proud men who wrote the charter of our liberties would not have been so eager to open their mouths for royal inspection. I dissent.”