U.S. Attorney Ronald Machen calls Kerry Khan “the ringleader of the largest bribery and bid-steering scheme in the history of federal contracting.”

On Thursday, Khan, a former Army Corps of Engineers program manager, will be sentenced for his role in a bribery and money-laundering scam that involved more than $30 billion in bribes and kickbacks. From the spring of 2007 until he was arrested in October 2011, Khan was paid more than $12 million.

But he can’t spend it now. He’s been incarcerated since his arrest. He pleaded guilty in May 2012 and could serve more than 15 years in prison for his crimes. Another former Army Corps program manager, Michael A. Alexander, got six years after pleading guilty to the kickback scheme last year. A third unnamed public official also was involved, as were others not in government.

Khan is one of the biggest crooks in federal government corruption cases, but he’s certainly not alone. Since Machen took office in 2010, more than 125 people have been convicted on federal corruption charges.

“Corruption generally is a priority of this office,” Machen said in an interview. While he’s probably better known locally for going after members of the D.C. Council, corruption among federal officials also keeps him busy.

“It sounds like a cliche,” he said, “but it really does tear at the fabric of our democratic process.”

It is a cliche. But when Machen talks about corruption, you have to believe it really eats at him. He leans forward in his chair and makes it clear that corruption will not be tolerated.

“We attack it aggressively,” he said.

A current case involves Michael Todd Sestak, a Foreign Service officer who was arrested in May for allegedly selling U.S. visas. Sestak worked in the U.S. Consulate in Ho Chi Minh City, Vietnam, where he was central to a scheme that charged applicants $20,000 to $70,000 for a visa, according to Machen’s office.

Apparently, the target market was Vietnamese people who could not get visas honestly but were rich enough to pay big bucks to get here dishonestly.

“Sestak received several million dollars in bribes in exchange for approving the visas,” a statement from Machen’s office said. “He ultimately moved the money out of Vietnam by using money launderers through off-shore banks.” Two other people, not federal employees, also were charged.

Sestak’s attorney, J. Michael Hannon, had no comment on the case.

In the past two years, Machen has racked up several guilty pleas and convictions of officials and contractors in federal corruption cases, including:

●Former U.S. represenative Jesse L. Jackson Jr. (D-Ill.). He will be sentenced in August for using campaign funds to pay for items such as fur capes, jewelry, appliances, furniture and cool stuff like Michael Jackson’s fedora.

●Mark Adams of Fort Washington, a former U.S. Agency for International Development contractor. In March, he was sentenced to 51 months in prison for embezzling more than $1 million from a global health program. His wife, Latasha Bell, also was in on the scheme involving bogus invoices for no work.

●Ramon S. Davila, a former contract background investigator for the Office of Personnel Management from Fredericksted, St. Croix, in the U.S. Virgin Islands. He pleaded guilty last month and was among 17 others who have been convicted during the past four years in cases involving falsified background checks of individuals seeking security clearances.

●James M. Woosley of Tucson, former acting director of intelligence for Immigration and Customs Enforcement in the Department of Homeland Security. A year ago, he was sentenced to 20 months in prison for a scheme involving fraudulent travel vouchers. Other federal employees and a contractor pleaded guilty to related charges — Ahmed Adil Abdallat, a former ICE supervisory intelligence research specialist; William J. Korn, a former ICE intelligence research specialist; Stephen E. Henderson, a former ICE contractor; and Lateisha M. Rollerson, a former assistant to Woosley.

“We’ve done a lot in a lot of different areas, because we want to make sure that people understand that when they have an oath and obligation to the United States, they have to fulfill it,” Machen said. “And if they don’t, there’s going to be consequences.”

He wants this message to get out: “If you engage in this sort of activity in D.C., it’s just not worth it, because they [his prosecutors] are very aggressive, they are very dedicated and they are very good at what they do in prosecuting these cases.”

You know if that applies to you.●

Twitter: @JoeDavidsonWP

Previous columns by Joe Davidson are available at wapo.st/JoeDavidson.