Over the past year, the ranks of people working part-time jobs by choice — as opposed to business-driven factors — has grown by more than one million, the fastest pace in at least two decades.

The timing with ObamaCare’s first year of subsidies to buy health insurance is likely more than coincidental. While analysts on the left and right have sparred over whether businesses have shifted to part-time jobs to limit liability under ObamaCare, no one disputes that the law will lead more people to choose to work part-time. Any disagreement is over whether the law should get credit for making less work possible or blame for making work less financially rewarding.