by Corey G. Johnson, design by Anna Donlan

For years, some of America’s most iconic gun-makers turned over sensitive personal information on customers — without their knowledge or consent — to the gun industry’s main lobbying group. Political operatives then employed those details to rally firearms owners to elect pro-gun politicians running for Congress and the White House.

The strategy remained a secret for more than two decades.

In a series of stories in recent months, ProPublica revealed the inner workings of the National Shooting Sports Foundation’s project, using a trove of gun industry documents and insider interviews.

We also showed how the NSSF teamed up with the controversial political consulting firm Cambridge Analytica to turbocharge its outreach to gun owners and others in the 2016 election.

Additional internal Cambridge reports obtained by ProPublica now detail the full scope and depth of the persuasion campaign’s sophistication and intrusiveness.

The political consultancy analyzed thousands of details about the lives of people in the NSSF’s enormous database. Were they shopaholics? Did they gamble? Did women buy plus-size or petite underwear?

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The alchemy had three phases.

Some of the data, excerpted here, was basic information you might find on a census, like marital status or ethnic group.

But the data also contained much more specific information about a person’s aesthetic preferences, purchasing habits and hobbies.

Other data highlighted consumers’ personal opinions, histories and even vices.

How Cambridge converted those tiny bits of data into massive political wins has never before been made public. Its methods raise disturbing questions about how our personal data can be used to manipulate us.

“There is a natural desire to stay anonymous and keep your own information, and this is such a violation of that,” said Calli Schroeder, privacy specialist at the Electronic Privacy Information Center.

The NSSF has said its “activities are, and always have been, entirely legal and within the terms and conditions of any individual manufacturer, company, data broker, or other entity.” Larry Keane, senior vice president of the NSSF since 2000, said the trade group’s 2016 voter outreach campaign involved only commercially available data.

But Cambridge emails and a report on the NSSF campaign said the data included 20 years of information about gun buyers harvested from manufacturer warranty cards given........

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