Two senior Justice Department officials appeared today before federal Judge Emmet Sullivan in Washington to defend the work of their prosecutors in a narcotics trafficking case.

But the mercurial Sullivan never gave them a chance to explain. Instead, he posed more questions for the government to answer in a brief due by July 10.

Paul O’Brien, chief of the Narcotics and Dangerous Drug Section, and Richard Weber, chief of the Money Laundering and Asset Forfeiture Section, appeared in support of prosecutors Paul Laymon and Wanda Dixon. Sullivan — perhaps still hearing the echos of applause for his role in uncovering Brady violations in the Ted Stevens case — is doggedly questioning whether the prosecutors violated the Brady rights of Zhenli Ye Gon, a Chinese-born Mexican businessman charged with conspiring to manufacture heaps of methamphetamine bound for the U.S.

The case has been on the brink of trial on several occasions. But last week the government moved to dismiss the case, citing Mexico’s extradition request and “the prospect of a very lengthy sentence” for Ye Gon if he’s convicted south of the border, according to court documents.

Also in that motion to dismiss, the government revealed ”evidentiary concerns” — foremost among them that a key government witness recanted more than a year ago. This is what got Sullivan’s attention.

Ye Gon’s defense team, which includes Manuel Retureta and A. Eduardo Balarezo, has asked ^[1] Sullivan to dismiss the case with prejudice, citing the government’s failure to disclose these “evidentiary concerns” in a timely manner. The Justice Department strongly denies ^[2] any wrongdoing. Brady rights kick in only if a trial is scheduled and fairly imminent, the government has argued.

Sullivan asked whether the Justice Department’s assertions that it had worked hard to produce evidence should be “viewed with skepticism.” Noting the complexity of the case — evidence and witnesses are sprawled across the globe — Sullivan asked how the defense could make use of the newly disclosed information four weeks before the case was set for trial. He also asked the government to explain how Ye Gon’s lawyers could have come by the information through other means or sources.

“All of this raises questions about whether the government ever intended to abide by its constitutional obligation” to turn over that information, Sullivan said, reading from prepared remarks, as he did in the Stevens case.

The judge cited a passage in the U.S. Attorneys’ Manual, which requires that prosecutors take a broad view of materiality and err on the side of disclosure. ”How does what the government did in this case comport with the manual” or Attorney General Eric Holder’s repeated pronouncement that the mission of prosecutors is not to win cases “but to do justice?” Sullivan asked.

He noted that the Ye Gon case was the second in three months in which the government was asking him to dismiss a case after Brady and Giglio issues had been raised. The first, of course, was the case against former Alaska Sen. Ted Stevens. It was O’Brien who led the DOJ internal investigation of the handling of evidence by the Stevens prosecutors and who stood before Judge Sullivan in April ^[3] and apologized in open court for the errors that led to dismissal of the high-profile public corruption case.

The judge mused that it appeared the government’s approach is to withhold material, until it gets caught in the act, and then move to dismiss. ”That would be shocking,” he said.

He also asked  whether prosecutors violated D.C. rules of professional conduct by potentially making false statements to the court in a previous hearing and in a bill of particulars.

O’Brien approached the podium once Sullivan finished and told the judge that he disagreed with the defense team’s characterization — and by implication, the judge’s — of the prosecutors’ behavior. His silence, he said, should not be confused for acquiescence.

“I’m just raising points,” not making any findings, Sullivan said. He then asked O’Brien whether there could ever be a Brady violation without a trial date.

O’Brien said Brady, “at its core, is a trial right.” The Justice Department  argued in a brief last week that due process is satisfied as long as the material is disclosed in time for the defendant to make effective use of it at trial. (Click here ^[4] for a copy of the brief.)

Sullivan set a hearing in the case for July 30.