You may now wish social media did not possess your personal information. But you probably surrendered your privacy when they asked you, and even after you “delete” it, they’ve still got your data. This we learn from Facebook’s sale of private data to the British data-mining firm Cambridge Analytica, which got Russian money to skew the 2016 election.

Cambridge Analytica’s ex-chief claimed the techniques, going back to 2014, from “psychographic profiles” worked, but others suspect they achieved little. For negative publicity, he also advised prospective clients (actually, British TV journalists) to hire Ukrainian women as honey traps. Wow, one-stop shopping for lechery, procuring, electoral manipulation and a Russian connection. Gosh, I hope this reputation does not rub off on the Republicans.

The mystery of how Russian cyberpenetrators got so much U.S. personal data to target their deceptive advertising is now solved: Facebook delivered it to Cambridge Analytica, who worked with Prof. Aleksander Kogan of both Cambridge and St. Petersburg universities. Isn’t that foreign interference in U.S. elections? Shouldn’t Cambridge Analytica register as foreign agents?

Facebook, Google and the like provide valuable services to consumers — for free. So they can claim they need revenue streams to support their popular services. But data sales far exceed that; they make the social media fantastically profitable, and their values soared. Data mines are the new gold mines.

Sales of data sets — in this case, of 50 million Americans, without their permission or even knowledge — dwarf advertising sales. Individual social-media users are not the customers; they’re products, for sale to data miners, who use them to snare unsuspecting voters.

Because the social media, like opioids, are addictive and manipulative and contribute to our current polarized mistrust, we are entitled to defend ourselves against them. A first, simple personal safeguard: Participate in NO surveys — online, telephone or social media. Some victims are suing Facebook; let’s see if it works.

More citizens call for regulation of the social media as a public utility, like radio and television. The European Union is introducing new regulations requiring social-media transparency and individuals’ permission to use their data. The Obama administration proposed a digital bill of rights, but Congress caved to industry lobbyists and blocked legislation.

Passing and enforcing regulations will be difficult. Facebook assured us for years that privacy was well-guarded. Regulators, now more toothless than ever, may not detect what’s going on behind corporate secrecy. Example: The SEC investigated Bernard Madoff six times but didn’t even know what questions to ask. Each time, Madoff got a clean bill of health until the market collapsed in 2008.

We might try guerrilla warfare: Feed the social media inaccurate information, making the data set sufficiently unreliable that potential buyers — political or commercial — will not trust it and pay money for it. This breaks no law, and they cannot sue you.

With fewer buying their data, social-media revenues and stock values will drop — Facebook’s already has — and may force them to clean up their act. It could also crimp the social media. I can live with that since I don’t even know how to use them. Too old.

Bogus telephone pollsters run parallel to social media. How can you tell which are bogus? Someone recently called me claiming to be from Gallup. I should have instantly disbelieved her and hung up, but I answered a few questions. She concluded by asking if I was Mister So-and-So (probably the previous phone number’s owner). I said I wasn’t but should — following my own devious advice — have said I was.

The telephone survey was worthless, and in two ways. Never bothering to update phone listings, they thought

I was someone else and based their questioning on that mistake. They also gave themselves away by looking for a particular person, which violates polling’s scientific basis: randomization, pioneered by Gallup in the 1930s. But it is useful for profiling. Gallup confirmed that they are constantly being “spoofed” and doing their best to fight it.

Even legitimate polls have accuracy problems, because surveys record only those who wish to be included. “Self-selection” has always plagued survey research and helps explain the poor predictions of recent elections. In our climate of mistrust, fewer than half respond to telephone surveys. Many Trump voters misstated their voting intentions, throwing the polls off. Expensive, old-fashioned face-to-face polling was better.

We need standards — contractual, regulated or both — for social-media and telephone data gatherers on how responses will be used, how widely they will be shared and what rights individuals have to authorize use of their personal data. As a political scientist, I want good survey data and worry that abusers ruin it.

Eugene Burdick’s 1965 novel “The 480” portrayed a data-driven techno-fascism. Now billionaires hire data miners to tilt elections. One good sign, however: Facebook and Google are no longer seen as beneficent techno-liberators in T-shirts but as greedy exploiters of our personal information to the detriment of privacy and even democracy. It’s fun watching them squirm.