When the nation’s largest insurer announced its departure from a few Obamacare state exchanges last year, the law’s defenders pooh-poohed the development as a blip on the radar. Then the health insurance giant pulled out of almost all markets, forcing apologists to insist that all was well because UnitedHealth’s overall Obamacare marketshare was relatively small. Next, the company said it was closing up shop within Covered California, the massive exchange in America’s largest state. And now we get word that another enormous insurer is edging away from participation in the law — withdrawing not just from Minnesota’s Obamacare exchange, but from the state’s entire individual-based market.

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