Credit: AFP

A few months ago, you accidentally defaulted on a phone bill. The mistake affects your credit score: It’s hard to get a loan. You can no longer make jokes about Marco Rubio on Twitter; such remarks will algorithmically define you as a libertarian loon—another sort of person likely to default on social obligations. After a couple of close friends miss their student loan repayments, you can’t even travel: your social circle is now all “discredited, unable to take a single step.”

This is the incipient scenario in China, whose state-backed “social credit scheme” will become mandatory for all residents by 2020. The quoted text is from a 2014 State Council resolution which promises that every involuntary participant will be rated according to their “commercial sincerity,” “social security,” “trust breaking” and “judicial credibility.”

Some residents welcome it. Decades of political upheaval and endemic corruption has bred widespread mistrust; most still rely on close familial networks (guanxi) to get ahead, rather […]