So why is Anthem Blue Cross raising the premiums of its California customers by as much as 39%? Here’s an argument for an “individual mandate” requiring everyone to have insurance, as well as a case for making sure this coverage is affordable.:

Anthem said its costs have been driven up in part because the weak economy has led many people in good health to forgo coverage, leaving those with greater medical needs in its pool of customers.

UPDATE: Our friend Jonathan Cohn digs deeper: