Crime rates in the United States have fluctuated over the past 20 years but have done so around a fairly stable mean. The stability in crime rates is at marked variance with the general public view that the crime problem is becoming more serious and is also in sharp contrast to recent incarceration trends. The key issue is why crime rates have remained stable in the face of dramatic increases in the incarceration rate. Four possible explanations are offered to address this issue: (1) crime rates would have increased significantly were it not for the growth in incarceration; (2) the impact of incapacitation is diminished because the additional people who have been incarcerated (primarily drug offenders) would not have contributed significantly to crime rates if they were on the outside; (3) incarceration has criminogenic influences; and (4) incarceration has diminished deterrent effects. A simple model that incorporates opportunity and individual choice in crime commission is described in an appendix. 15 references, 16 notes, and 5 figures