On Friday, Attorney General Jeff Sessions issued a memo shifting the US Department of Justice’s (DOJ) charging policy, suggesting that serious charges and long sentences for drug crimes will reduce violent crime and combat the opioid crisis. The previous guidance, handed down by Eric Holder in 2013, called for prosecutors to avoid charges in certain instances that could trigger drug mandatory minimums.

Because the federal prison population is finally in decline, the financial cost of this new policy may come as a shock: increasing the prison population is deeply out of line with President Trump’s plans to trim the budget and something early versions of the budget don’t seem to account for.

For nearly 40 years, attorneys general have issued guidance on how federal prosecutors should decide what charges to bring and what sentences to seek, shifting back and forth from recommending individualized assessment, to rejecting individualized assessment in favor of consistency, to Eric Holder’s most recent message about avoiding mandatory minimums. It’s a pendulum effect that takes place absent Congress passing comprehensive reforms affecting mandatory minimums for drug sentences.

These messages don’t go ignored by prosecutors. Following Holder’s recommendations, the number of people convicted of charges that carry mandatory minimums decreased. In 2016, just under half of people convicted of drug offenses faced a mandatory minimum penalty, the lowest proportion since the US Sentencing Commission started keeping track in 1993, contributing to the first declines in the federal prison population in decades.

By contrast, Sessions is calling for prosecutors to charge defendants with the most serious provable crimes and seek the most severe penalties possible. He said on Friday that prosecutors will be (ironically) “unhandcuffed” and “empowered” to enforce the law more aggressively.

It seems inevitable that the Sessions memo will stem prison population decline and likely lead to an increase in prosecutions and imprisonment, in no small part through an increase in sentence lengths because of drug mandatory minimums.

But how will the Trump administration pay for the resulting increase in the federal prison population? With more defendants charged with crimes tied to longer sentences, the impact of a directive like this could ripple for decades.

Meanwhile, the administration’s preliminary budget mentions “almost a billion dollars” in savings due to the currently shrinking prison population. It’s an issue previous attorneys general haven’t faced because none came into their positions while the prison population was shrinking. The savings Sessions’s policy stands to eliminate were the first from the Bureau of Prisons in decades.

Sessions can’t have it both ways. If the Trump administration announces savings in the budget, those are dependent on sustaining federal prison population levels, if not continuing recent reductions in incarceration.

Failing to account for the cost of an impending rise in the prison population shows a shortsightedness that may be matched by a lack of hindsight: in proposing prosecutors take an aggressive stance on drug crimes in particular, Sessions is advocating an approach that’s proven ineffective over the nearly 50 years since the “War on Drugs” began.

Sessions also argues that a more aggressive approach to drug charges and sentences will get the most dangerous, violent people off the street, but our research suggests differently. Almost half of people serving time for drug crimes in federal prison have little to no previous criminal history, and Congress’s bipartisan Charles Colson Task Force on Federal Corrections was firm in its recommendation that drug mandatory minimums be “reserved for only the most serious offenses.”

Finally, Sessions’s guidance for prosecutors is inconsistent with what’s going on in the states. Even among Republican governors, the trend is moving toward legislation that reduces punishments for drug crimes. This administration considers passing responsibility back to the states a priority, but seems to be providing guidance at the federal level that runs counter to what states are calling for.  

The only way to resolve the incongruity between the reforms states are passing and the perpetual pendulum swing of charging policies for drug offenses is if Congress passes legislation to reform drug sentencing, particularly mandatory minimum penalties.

In the meantime, we’ll quite literally pay the price. Aspiring to balance the DOJ budget on the back of a possibly fleeting prison population decline will have significant implications for funding other valuable DOJ programs.

So when Sessions’s charging policy inevitably increases the prison population and the billion dollars in “savings” dissolves, the DOJ will have to scramble to cut from other places to make up the difference. Historically, cuts to the Bureau of Prisons programming and treatment designed to reduce recidivism have been at the top of the list—a questionable outcome in the interests of public safety.