Is it actually relevant to think about infrastructure "failing"? In many instances-such as the blackout that occurred in much of Northeastern United States in 2003-the infrastructure still exists, but it is not working in a reliable or sustainable way, or is poorly maintained. However, there are two circumstances in which infrastructure might be described as having "failed"-when there has been a gradual erosion of service or state of repair, and when there has been a sudden and complete failure that may or may not have resulted in a complete loss. This distinction is important because, in the former instance, the infrastructure remains in existence and the concern is potentially more about its ownership and associated financing. In the latter circumstance, when there has been a sudden and complete failure, the concern might be more about the ability to react to failure and, if there has been a total loss, the obligations and financing of replacement infrastructure. These are considerations regardless of whether the infrastructure is publicly or privately financed.