Noticing the continued decline of the federal prison population (for now) ... and a story embedded with intricacies

Over at the Washington Post's WonkBlog, Keith Humphreys has this important little discussion of the federal prison population under the headlined "The number of people in federal prisons is falling, even under Trump."  Here are excerpts (with a few lines emphasized for some follow-up commentary):

When states began shrinking their prison populations almost a decade ago, the federal prison system was still growing each year and thereby undermining progress in reducing mass incarceration. But in the past four years, the federal system has cut its inmate population by one-sixth, a decrease of over 35,000 prisoners.

Because criminal justice is mainly the province of the states, the federal prison system holds only about 13 percent of U.S. inmates. Yet that is still a significant number of people in absolute terms: The system held 219,300 inmates at its peak in 2013. Four subsequent years of significant contraction dropped the federal inmate population to 184,000 by the end of 2017.

Obama-era changes to drug crime prosecution and sentencing coupled with a historic level of clemency grants to federal inmates by President Barack Obama helped bring the federal prison system to its lowest population size since mid-2004 and its lowest incarceration rate (i.e., adjusted for population) since the end of 2002.

Given President Trump’s penchant for “tough on crime” rhetoric, some observers may find it surprising that the federal prison population kept dropping under the first year of the Trump administration. The most likely cause is also the most obvious. When a nation is blessed with two decades of falling crime rates, this eventually translates into lower incarceration rates because there just aren’t as many offenders to arrest, charge and imprison.

Whether the federal prison population continues to decline will depend in part on Trump administration policies. Attorney General Jeff Sessions recently reversed the Obama-era policy of avoiding mandatory minimum sentences in low-level drug cases, which could result in some future growth in the federal inmate population even if crime continues to fall.

The other key determinant of the federal prison population’s future is whether Trump will make use of his powers to pardon or commute the sentences of federal inmates. He only did so for one inmate this year, but that doesn’t necessarily mean he won’t grant more clemencies later.

Though it is important and useful to notice that the federal prison population continued its downward trend in the first year of the Trump Administration, it is not quite accurate to attribute this reality to either "two decades of falling crime rates" or to Presidential commutation practices.  For starters, we had falling crimes rates in the decade from 1992 through 2002, and yet the federal prison population more than doubled from less than 80,000 inmates in 1992 to more than 163,000 inmates in 2002.  And we had another decade of falling crimes rates from 2002 through 2012, and yet the federal prison population rose another 55,000 inmates in that period.  And, of course, crimes rates started ticking up significantly in 2015 and 2016.

Moreover, and perhaps even more importantly, there is actually a very limited (and quite unclear) relationship between the FBI's reported reductions in violent and property crimes — which is the data base for "falling crime rates" — and the federal criminal caseload which is primarily made up of drug and immigration and firearm and fraud offenses.  Indeed, in light of the empirics of the opioid crisis — not to mention increased marijuana activity thanks to state legal reforms — there is reason to speculate that federal drug offenses have actually been rising (perhaps significantly) in recent years.  The dynamics surrounding recent crime rates for federal immigration and firearm and fraud offenses are hard to assess, but that very reality is part of the reason it is hard to link federal prison population changes to what we know (and do not know) about crime rates.  But, without any doubt, there are still plenty of "offenders to arrest, charge and imprison" engaged in the activities that serve as the modern bread-and-butter of federal prosecution.  Though there are a range of linkages between various crime rates and various federal prosecutorial policies and practices, it is very hard to see and measure and assess with any confidence how basic criminal offending (especially as to classic state crimes) may directly impact the size of federal prison populations.

What we can effectively see and measure are changes in federal sentencing laws and federal prosecutorial practices, and these changes suggest a set of intricate stories help account for recent federal prison population changes.  For starters, the US Sentencing Commission enacted a set of broad retroactive changes to the federal drug sentencing guidelines, with crack guideline reductions in 2007 and 2011 and the "Drugs -2" reductions in 2014.  These changes reduced the sentences of, and is continuing to lead to the early release of, many thousands of federal prisoners.  In addition, and perhaps even more statistically important for the very latest federal prison data, federal prosecutors after 2012 began decreasing dramatically the number of cases getting all the way to federal sentencing.  According to US Sentencing Commission data, in Fiscal Year 2012, federal prosecutors brought over 84,000 cases to sentencing, whereas by Fiscal Year 2016, federal prosecutors brought fewer than 67,750 cases to sentencing.  And, especially with a slow transition to new US Attorney positions, it may take some time for the new Attorney General to ramp up yearly federal prosecutions (assuming he even wishes to do so).

In other words, the always dynamic stock and flow story of prison populations provides a somewhat more granular understanding of declines in the federal prison population.  Changes to federal sentencing laws made retroactive has had a significant impact on the "stock" of federal prisons.  (Prez Obama's commutations are a small part of this "stock" story, but not until they really got going in 2016, and in the end more than 25 federal prisoners got reduced sentences thanks to retroactive guideline changes for every prisoner who got a commutation from Prez Obama.)  And while guideline changes were reducing the federal prison "stock," it seems the prosecutorial policies announced by Attorney General Holder in 2013 — and perhaps other factors, including decreased national concerns about crime — finally began to reduce what had previously been, for two decades, an ever-increasing federal prison "flow."

I would predict that the May 2017 Sessions charging/sentencing memo could contribute, over time, to increasing both the stock and the flow of the federal prison population.  But other directions coming from Main Justice might complicate this story.  AG Sessions has urged US Attorneys to focus on violent crimes, and there may well be fewer of these cases to bring and they may take more time to prosecute than lower-level drug and gun and immigration cases.  But, of course, the AG has also expressed concerns about drug and gun and immigration cases, and he has been seeking to hire and empower more federal prosecutors in certain arenas.  I will be especially watching how all these developments ultimately impact the US Sentencing Commission's data on cases sentenced (and average sentence imposed) in order to try to predict where the federal prison population may be headed next.