From left to right: Chief Justice John Roberts with fellow justices Anthony Kennedy, Ruth Bader Ginsburg, Stephen Breyer and Elena Kagan at the 2014 State of the Union. (Photo by Larry Downing-Pool/Getty Images)

That Supreme Court ruling on cellphones was supposed to be reassuring. The government needs a warrant to search your phone, the court ruled.

But read Riley vs. California more closely and it’s just a little scary — particularly for those who pay little attention to what’s on their smartphones. If you don’t think your phone exposes your life-all of it-take it from the nation’s highest court.

Your phone, says the court, is your life. Cracking it open is even more revealing than rummaging through your home, which the Fourth Amendment’s protection against unreasonable searches was designed to protect.

Sure, your home holds a bunch of paper in files, your diary and some old credit card bills and prescriptions.

But your phone, the court reminded Americans, is a “mini-computer” stocked with information.

Your cellphone “collects in one place many distinct types of information — an address, a note, a prescription, a bank statement, a video — that reveal much more in combination than any isolated record.”

Your cellphone’s capacity “allows even just one type of information to convey far more than previously possible. The sum of an individual’s private life can be reconstructed through a thousand photographs labeled with dates, locations, and descriptions; the same cannot be said of a photograph or two of loved ones tucked into a wallet.”

Your cellphone’s data “can date back to the purchase of the phone, or even earlier. A person might carry in his pocket a slip of paper reminding him to call Mr. Jones; he would not carry a record of all his communications with Mr. Jones for the past several months, as would be routinely kept on a phone.”

Your cellphone may show an “internet search and browsing history” that could “reveal an individual’s private interests or concerns — perhaps a search for certain symptoms of disease, coupled with frequent visits to WebMD.”

Your cellphone can allow someone to “reconstruct” your “specific movements down to the minute, not only around town but also within a particular building. … ‘a wealth of detail about'” your “‘familial, political, professional, religious, and sexual associations.'”

Your cellphone has a range of apps that may reveal your political leanings, your “alcohol, drug and gambling addictions,” your “prayer requests,” whether or not you are pregnant or hope to be pregnant or have a romantic life or none.

The opinion: “The average smart phone user has installed 33 apps, which together can form a revealing montage of the user’s life.”

In 1926, the court said, Judge Learned Hand “observed … that it is ‘a totally different thing to search a man’s pockets and use against him what they contain, from ransacking his house for everything which may incriminate him.'”

But “if his pockets contain a cell phone, that is no longer true.”

That’s why police need a warrant to search your phone.

And this the court did not say: Search warrants are not that hard for police to get. They go to a judge or magistrate and argue that they have probable cause to believe there may be criminal activity involving you. They don’t have to prove you’ve done anything. You are not consulted.

Also, police need a warrant to search your phone but others — private investigators, industrial spies, identify thieves or your kid’s nosy friend (or your kid) — do not. The Constitution protects you from actions by the government, not anyone else.

And the court said police don’t always need a warrant. In “exigent” circumstances — a suspect texting an accomplice about a bomb or a child abductor who may have information about a child’s location on his phone — they need not waste time calling a judge.

The message from the court: Be careful what you put on your phone.