Several conservatives chided me for not recognizing that the increase in the number of people who say they're part-time for economic reasons is clearly due to the influence of the Affordable Care Act and its employer mandates. I think this aspect of the law is misguided and ought to be changed, but as you can see above the rise in part-time work happened well before the law was passed. It was part and parcel of the general economic decline that began in early 2008 and continued until the spring of 2009.
And my point is that this kind of thing is a sure sign of a demand shortfall. The part-time for economic reasons worker isn't unemployable. In fact, he's employed. And he says he's eager to work more hours at the same wage. But his employer doesn't have enough customers for that to make sense.