Last April, Steve Cook, the president of the National Association of Assistant United States Attorneys, appeared on a podcast hosted by Frank Gaffney, the conservative conspiracy theorist, and an early proponent of the myth that former President Barack Obama was secretly a Muslim.

Cook, 61, who was also chief of the Criminal Division for the U. S. Attorney’s Office for the Eastern District of Tennessee, was there to talk about his opposition to federal criminal justice reform legislation that would have reduced mandatory minimum sentences for nonviolent crimes, and that was close to passing with support from a bipartisan group of lawmakers.

At one point on the program, Gaffney, reflecting a preoccupation with Muslims, asserted that Obama’s use of his clemency power to commute the sentences of nonviolent federal prisoners freed “people who have been converted in prison to, not just to Islam, but to jihad.”

There is no evidence that anyone whose sentence was commuted by Obama later engaged in terrorism, but Cook did not correct his host. Instead, he appeared to accept the premise, responding that participants in the 2016 terror attacks in Paris and Brussels had come from neighborhoods known for drugs and violent crime.

“The link there is unmistakable,” Cook said.

Earlier this month, Attorney General Jeff Sessions quietly installed Cook as the associate deputy attorney general with a mandate to focus on violent crime. In that job, which does not require Senate confirmation, Cook is the top federal official working full-time on implementing President Donald Trump’s vow to curb “carnage” in American cities.

Cook’s trip from fringe podcast guest to Justice Department headquarters highlights the dramatic reversal in criminal justice reform resulting from Trump’s victory. Hardly a year after their views appeared close to consensus, sentencing reformers are sidelined. Advocates of a 1990s-era tough-on-crime strategies are setting policy.

Like Sessions, Cook is a fierce proponent of the crime-fighting theory that is responsible for our current era of mass incarceration. Lock up as many drug dealers and traffickers as possible, for as long as possible, and violent crime will subside, he maintains.

“When you put criminals in jail, crime goes down,” he told the Knoxville News Sentinel last year. “That’s what incapacitation is designed to do, and it works.”

Linking violent crime to drug crime — and both to potential acts of terrorism — is a way to further buttress support for a prosecutorial worldview that as recently as last year was widely viewed as out-of-date, overly punitive, racist, and ultimately ineffective.

In a brief interview with The Trace, Cook said he will work on “violent crime strategy” at the Justice Department. He declined to elaborate, saying he could not comment further because of his new post.

Steve Cook in February 2016. Photo: Tom Williams/CQ Roll Call

Cook spent seven years as a Knoxville, Tennessee, police officer. His 25 years as an assistant U.S. attorney there started in the early 1990s as violent crime rates, tied to a crack cocaine epidemic, peaked. Fellow prosecutors said his views align with many law enforcement officials who spent formative portions of their careers imposing the stiff mandatory sentences and believe their work reduced violent crime.

“This is what we do, and we know from our experience from the last 40 years what works and doesn’t work,” said Larry Leiser, who worked for Cook as vice president for policy for the assistant U.S. attorneys association.

Leiser said prosecutors need power to threaten long sentences to compel defendants’ cooperation against higher-level criminals.

“It’s a system that works pretty well from our point of view and that’s why we’re reluctant to change it,” he said.

Sentencing reform advocates greeted Cook’s appointment with alarm.

“We were all kind of like shocked. Like ‘Oh no, not him,’” said Debi Campbell, who works for the Families Against Mandatory Minimums, a nonprofit group. “It’s actually kind of scary.”

Campbell, who said she learned of Cook’s appointment through The Trace’s inquiry, testified at a Senate Judiciary Committee hearing alongside Cook in 2015. With Cook seated next to her, she described spending 16 years in prison for a nonviolent methamphetamine trafficking conviction. Campbell’s sentence relied on claims by a woman who testified against her and, in exchange, received probation.

Campbell looked on while Cook then maintained that mandatory minimums are necessary to compel cooperation against “higher-level participants” and that people prosecuted in federal court for drugs are inherently violent.

“The questions we should ask about releasing these violent and career offenders early are not if, but when, how many, and how badly citizens will be victimized as a result,” he said.

Cook’s argument boils down to an assertion that if violent crime dropped while prison populations rose, then imprisonment prevents violence.

Sentence reductions for people convicted of past crimes, even non-violent ones, would lead to greater bloodshed, he maintains.

“More criminals on the streets will result in more crime,” Cook said in his testimony at the Senate hearing.

When talking about how to stamp out crime, Cook sounds a lot like Sessions, an Alabama Republican who is both a former U.S. attorney and state attorney general. In the Senate, Sessions was one of Congress’ most prominent opponents of criminal justice reform.

Last week, with a memo to U.S. attorneys nationwide, Sessions began unraveling an Obama administration policy of granting federal prosecutors discretion over when to impose stiff gun and drug penalties.

“Many violent crimes are driven by drug trafficking and drug trafficking organizations,” Sessions wrote. “For this reason, disrupting and dismantling those drug organizations through prosecutions under the Controlled Substances Act can drive violent crime down.”

But research into the effects of incarceration does not support the Sessions/Cook worldview. Studies have found no evidence that keeping prisoners jailed for decades for nonviolent offenses reduces crime. Mass incarceration is, however, extremely costly. These truths, along with a long decline in the national violent crime rate, helped spur bipartisan backing for shorter sentences. Democrats and libertarian-leaning Republicans like Charles and David Koch and Senator Rand Paul of Kentucky backed the reform bills — joined by mainstream GOP figures like Senator Chuck Grassley of Iowa and Representative Bob Goodlatte of Virginia, the respective chairmen of the Senate and House Judiciary Committees.

So why the retrenchment toward 1990s-era policies? A sharp increase in violent crime in many large cities, most notably Chicago, has captured national attention. And rhetorically, the notion of locking criminals up is an easier sell to many people than confronting the many contributors to urban crime: poverty, vanishing economic opportunity, easy access to guns, gang warfare (some of which is, in fact, drug-related), and even boredom. Incarceration is also easier for conservatives to embrace than closing the loopholes and attacking the straw purchasing, theft, and trafficking that keeps high-crime neighborhoods well-stocked with deadly firepower.

Molly Gill, director of legislative affairs at Families Against Mandatory Minimums, said Cook’s logic has the virtue of “straightforward simplicity.” That counts with a president who claims, without elaborating, that rising gun violence in Chicago is “very easily fixable.”

Cook’s arguments on behalf of the assistant U.S. attorneys group laid the groundwork for this policy. But some of the talking points he has repeated to make his case for keeping people convicted of violent crimes locked up for as long as possible have been misleading. For instance, Cook consistently cited a 2014 Bureau of Justice Statistics study that he suggested found a 77 percent rate of recidivism — the tendency for criminals to commit new offenses — among violent criminals.

But that 77 percent figure applies to all criminals over five years and covers any new offense, the most common of which are parole violations that can stem from minor violations of release terms, like consuming alcohol. The study found the percentage of violent offenders arrested after their release for another act of violence was far less: one-third. The study also covered only state prisoners. Further research found that just 14.5 percent of released federal prisoners were later arrested for a violent crime.

The disparity between state and federal recidivism rates may reflect what is sometimes called “criminal menopause”: Men are most likely to commit violent crimes before age 24, with the likelihood falling as they get older. People convicted in federal court tend to get longer sentences. As they age, their imprisonment becomes an increasingly less effective means to stop crime, but a sure way to saddle the government with the costs of their housing and increased medical care.

Cook handles this complication by ignoring it. His argument contains only a glancing reference to the cost imposed on the government by his preferred policies.

John Pfaff, a law professor at Fordham University who studies crime and incarceration, said Cook also ignores the social cost of mass incarceration, from reduced life expectancy to damage done to the prisoners’ families.

“These are real costs, and they are discussed far too rarely,” Pfaff said in an email.

Gill, the sentencing reform advocate, said that as recently as last year, Cook “represented the far right fringe” on criminal justice.

Now, Cook is representing the U.S. Justice Department.