So employment is a power relationship, and high unemployment has greatly weakened workers’ already weak position in that relationship.

We can actually quantify that weakness by looking at the quits rate — the percentage of workers voluntarily leaving their jobs (as opposed to being fired) each month. Obviously, there are many reasons a worker might want to leave his or her job. Quitting is, however, a risk; unless a worker already has a new job lined up, he or she doesn’t know how long it will take to find a new job, and how that job will compare with the old one.

And the risk of quitting is much greater when unemployment is high, and there are many more people seeking jobs than there are job openings. As a result, you would expect to see the quits rate rise during booms, fall during slumps — and, indeed, it does. Quits plunged during the 2007-9 recession, and they have only partially rebounded, reflecting the weakness and inadequacy of our economic recovery.

Now think about what this means for workers’ bargaining power. When the economy is strong, workers are empowered. They can leave if they’re unhappy with the way they’re being treated and know that they can quickly find a new job if they are let go. When the economy is weak, however, workers have a very weak hand, and employers are in a position to work them harder, pay them less, or both.

Is there any evidence that this is happening? And how. The economic recovery has, as I said, been weak and inadequate, but all the burden of that weakness is being borne by workers. Corporate profits plunged during the financial crisis, but quickly bounced back, and they continued to soar. Indeed, at this point, after-tax profits are more than 60 percent higher than they were in 2007, before the recession began. We don’t know how much of this profit surge can be explained by the fear factor — the ability to squeeze workers who know that they have no place to go. But it must be at least part of the explanation. In fact, it’s possible (although by no means certain) that corporate interests are actually doing better in a somewhat depressed economy than they would if we had full employment.