The modern roots of the racial wealth gap can be traced back to the post-World War II housing boom, when federal agencies blocked loans to black Americans, locking them out of the greatest wealth accumulation this country has ever experienced. More recently, the bursting of the housing bubble and subsequent recession slammed minorities. In 2013, the median wealth of white households was 13 times the median wealth of black households, the widest gap since 1989.

Earlier this year, my colleague Annie Waldman and I took a close look at debt-collection lawsuits in three major American cities. We expected to see a pattern driven by income, with collectors and credit card lenders suing people most often in lower-income areas.

But income was just half the story. Even accounting for income, the rate of court judgments from these lawsuits was twice as high in mostly black communities as it was in mostly white ones. In some neighborhoods in Newark and St. Louis, we found more than one judgment for every four residents over a five-year period. Many were families who, knocked off their feet by medical bills or job loss or other problems, had simply been unable to recover.

When debts turn into court judgments, plaintiffs gain the power to collect by cleaning out bank accounts and seizing wages. Federal and state laws generally don’t protect anyone but the poorest debtors, and because judgments are valid for a decade or more, the threat of garnishment can linger for years. The paycheck from that new job may suddenly be slashed and savings may disappear.

Sometimes the consequence of not having the money to pay a bill is immediate: The power goes out. In a 2009 national survey of lower-income households by the federal Energy Information Administration, 9 percent of blacks reported having their electricity disconnected in the previous year because they had been unable to pay. For whites, the number was less than 4 percent, according to an analysis of the survey by the National Consumer Law Center.