The Justice Department's lawsuit to block AT&T's purchase of Time Warner has a trial date: March 19, 2018.

In a short initial status conference on Thursday in the United States District Court for Washington D.C., Judge Richard Leon said the trial will last around three weeks and that he expects a decision in late April or May.

Either way, the decision would come after the current April 22 cutoff date for the acquisition, after which AT&T must pay Time Warner a $500 million breakup fee unless the two companies extend the deadline, which they have already done once.

"We thank the Court for its deliberate and expeditious approach to this matter," AT&T's General Counsel David McAtee said in a statement. "We understand and appreciate how busy the Court is, and we will promptly discuss the Court's post-trial schedule with Time Warner. We are committed to this transaction and look forward to presenting our case in March."

Lawyers for the government and the two companies had sparred in motions before the hearing over the trial date, with the Justice Department seeking a later start to the case, in May, and the companies wanting it to begin earlier than it will now in an effort to hit the deadline.

Still, both sides agreed that even Leon's compromise date means that they will have to cram to be ready.

"We understood what we are getting into," one of the DOJ's lawyers, Craig Conrath said.

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Leon also acknowledged the burden the case will place on both legal teams, saying he himself will likely be working over the holidays as a result of the timing.

Leon also noted in several comments the gravity of the case, pointing out for instance that his court room hadn't been as packed as it was for the hearing in some time.

"This is not a normal case from many perspectives," he noted. Leon said there will be status hearings every two weeks because "this is that important of a matter."

A George W. Bush-appointee who has served on the court since 2002, Leon has dealt with big media mergers before. He reviewed the settlement that allowed the Comcast-NBC Universal merger to go ahead, and was critical of the deal before eventually signing off on it.

In its suit, the DOJ argues that the deal violates antitrust law because AT&T would likely "use its control of Time Warner's popular programming as a weapon to harm competition."

The government alleges that the deal "would result in fewer innovative offerings and higher bills for American families."

AT&T disputes that and has said it offered remedies to the Justice Department, similar to what the department had accepted in the Comcast-NBC Universal deal. AT&T and Time Warner also pledged to offer arbitration to competitors if distribution negotiations broke down, and promised to never "go dark" in the middle of such negotiations.

During the hearing, Leon applauded both sides for managing to work together to settle a motion for a protective order regarding protecting confidential information from improper disclosure and said he hopes that is how future motions will be resolved.

"I encourage you to continue to work well together," he said, though he also chided both sides for bringing legions of lawyers into the hearing.