When I wrote about the question of jobs versus culture being at the root of the precipitous decline of marriage among poorer Americans, Bearing asked to what extent the "war on drugs" and mass incarceration might be at fault.
Certainly, the number of Americans in prison has skyrocketed in the last 35 years, and the vast majority of those extra inmates are male. There are now roughly 1% of American men in some sort of correctional facility, and another 2% or so currently in parole.
A significant percentage of those men are African American. 2.2% of the Black population is in prison, and since we can assume the vast majority of those are men, via simple math we could call it around 4.5% of Black men. By comparison. 0.4% of the White population is in prison, or about 0.8% of White men. (This is the result of a range of factors. There are some studies indicating that racial minorities tend to get longer sentences for similar crimes, however it's also the case that racial minorities commit a number of crimes at higher rates.)
To what extent high recent incarceration rates are the result specifically of the war on drugs, I don't know, and again I suspect the answer is complicated. Megan McArdle (who is an advocate of legalizing drugs) wrote the other day that people are in general mistake to believe that a lot of the people in prison are there for simple possession of drugs. Of the population of people actually serving time, apparently a lot are there for drug offenses, but also additional ones that most people agree are a problem (domestic abuse, theft, etc.) There's an extent to which the illegality of drugs begets other crime, since it creates a niche for organized crime to sell drugs and then to fight over who controls the drug market. However, drug use (which would doubtless go up with legalization -- after all, drinking went down during Prohibition) can also get tied in with crime in other ways: people steal to get money for drugs (or for alcohol), serious addiction cuts into the ability to hold jobs. etc.
So I'm not sure precisely to what extent the war on drugs can be blamed as the primary reason that our incarceration rate is high. But let's get back to the question of whether the incarceration rate is what's causing people to have children out of wedlock. Are all the men locked up, and so the only alternative is to have children out of wedlock?
Well, both graphs move around the same. Here's the out of wedlock birth rate again:
There are some differences: incarceration picks up about ten years after out-of-wedlock births do. Incarceration has actually been going down for the last few years, while out-of-wedlock births are still going up. However, there is a similar directionality to it all.
I don't have a definitive answer.
I would however note:
The number of people who are caught up in the prison system (or are on parole, or have been) is significantly smaller than the shortfall in marriages. I've found figures ranging from 11% to 30% for the percentage of African American men who spend time in jail, prison, on parole or on probation at some time between 20 and 34. Even if we assumed that this renders all of those men completely unmarriageable, that's still not up there with the 70%+ out-of-wedlock birth rate. But the intersection of crime and imprisonment, and the way that the latter often leads right back to the former, is definitely one of the forces which is making society much worse in certain parts of society.
And, obviously, none of these answers stand alone. Even if incarceration and its aftereffects is one of the things to which people are responding, the basic idea that it's an viable life alternative to simply have a family without getting married is a changed cultural idea.