Attorney General Eric Holder. (Pablo Martinez Monsivais/AP)

LIBERALS AND conservatives have learned from the drug war’s failures. More jail time may result in less crime, but the costs can be too high. Harsh punishments often catch street-corner dealers, not drug kingpins. The drug war’s foremost legacy is a skyrocketing prison population; the number of drug offenders in federal prisons has increased 21 times since 1980.

Spurred by this alarming reality, the U.S. Sentencing Commission unanimously voted last week to give nearly 50,000 inmates the chance to reduce their drug sentences. This came after an April decision to lower sentencing guidelines, the advisory rules given to judges, by an average of one to two years for drug-related crimes.

The commission’s decision begins to swing the pendulum back from the days of excessive punishment. So does Attorney General Eric H. Holder Jr.’s push for prosecutors to avoid activating mandatory minimum sentences when charging low-level drug crimes and for an expansion of clemency.

Yet the commission’s guidelines aren’t binding, and Mr. Holder’s department policies could be overturned by his successor. The core of the problem — overly tough mandatory minimum sentences and the difficulty in reintegrating ex-prisoners into society — can be addressed only by Congress.

Luckily, two bills are pending that precisely address these issues.

The Smarter Sentencing Act would reform how prisoners are sentenced. Currently, a defendant convicted with just 10 grams of certain drugs and one prior felony drug offense must receive at least 20 years in prison. The bill helps correct what Mr. Holder called “draconian” minimum sentences, halving them for many drug crimes and expanding exemptions for nonviolent offenders with little criminal history. These mandatory minimums, implemented in the 1980s, did not help enhance public safety as the amount of drugs caught by law enforcement steadily increased. States such as Michigan and Delaware have wisely amended their laws.

The second bill, the Recidivism Reduction and Public Safety Act, reforms the way prisoners reintegrate into society. It expands prison jobs, academic classes and drug treatment programs that allow inmates to prepare for life after jail. Recidivism rates are high because ex-prisoners are often treated as second-class citizens, unable to find jobs to sustain themselves. This bill also ties early-release credits to the successful completion of recidivism-reduction programs.

Sponsors of these two proposals are negotiating on whether to bundle them together. Whether that is successful or not, both bills should pass. They will help lower the crime rate in the long run, bring proportionality back into punishments and save millions of dollars a year.

“Conservatives should lead on this,” Grover Norquist, who supports criminal justice reform, told us. “Liberals don’t have a track record on crime. We do.”

Perhaps the Republicans stalling on these bills should listen to Mr. Norquist. Some lawmakers think the earliest chance of passage would be in 2015, but there’s no reason it can’t be done this year.