WASHINGTON — Deputy Attorney General Rod Rosenstein told the Anti-Defamation League’s National Leadership Summit on Sunday that law enforcement must study the Holocaust “not only to understand the depths of depravity that people can perpetrate, but also as a reminder to guard against the risk of moral corruption in our own time.”

“The importance of enforcing the rule of law is a central lesson of the Holocaust,” he said, noting Lutheran pastor Martin Niemöller’s quote on his early failure to stand up for groups targeted by the Nazis: “Then they came for me — and there was no one left to speak for me.”

“We must defend the rule of law at all times, even when it is difficult, so it will be there for us when we need it,” he added.

Rosenstein touted the Justice Department’s work “aggressively” pursuing hate crimes, with more than two dozen defendants and 22 convictions since January 2017.

Anti-Semitic hate crimes, he noted, increased 12 percent from 2014 to 2016. “Anti-Muslim hate crimes doubled from 2014 to 2016. We are aggressively investigating and prosecuting those cases, as well.”

“It is important to collect accurate data so that we understand the scope of hate crimes. Last year, the FBI trained nearly 900 law enforcement agencies about hate crime data collection. Within the next three years, the FBI plans to consolidate all crime reporting in a single interface that includes hate crimes,” he continued. “We are also working closely with state and local authorities to prevent hate crimes. The FBI’s Civil Rights Unit developed a hate crime-training program for law enforcement agencies and community organizations around the country.”

Rosenstein noted that the Civil Rights Division resolved discrimination cases involving mosques and zoning in Michigan, New Jersey, and Illinois. “We have 10 ongoing investigations regarding discrimination against mosques and synagogues,” he said.

“The Department of Justice fully supports the men and women of law enforcement. The overwhelming majority of them are courageous and honorable public servants. But in those occasional instances where police officers violate their oaths, our department holds them accountable,” the deputy attorney general added, offering as an exampled the 20-year sentence for former officer Michael Slager, who shot Walter Scott in the back in North Charleston, S.C., in 2015.

Last year, DOJ’s Civil Rights Division conducted a four-day intensive hate crime-training program for federal prosecutors, and Rosenstein invited the ADL’s help to hold more events in the future.

“A shared commitment to the pursuit of justice under the rule of law is the central bond that ties Americans together,” he said.