The Justice Department declared today that Texas’ new Congressional map violates the Voting Rights Act but deferred giving any details on its legal reasoning until later this week.

The department’s court filing is the first major indication that the Obama administration will go to the mat over the controversial new map.

Texas is one of several states that require federal pre-clearance for any changes to voting laws, including redistricting, to ensure they adhere to the Voting Rights Act. Lone Star State officials filed their pre-clearance case directly with the U.S. District Court for the District of Columbia in July, bypassing the Justice Department by suing the agency in court instead.

The Justice Department responded for the first time on the Texas case by stating its opposition to the map as violating the Voting Rights Act. But it declined to say which House districts are illegal in its opinion, leaving those details to be spelled out later in the week.

The Justice Department stated the proposed map does not maintain or increase “the ability of minority voters to elect their candidate of choice in each district protected by Section 5.”

“Defendants deny that the proposed Congressional plan complies with Section 5 of the Voting Rights Act,” the brief said.

The Justice Department stated that it will present “districts that remain at issue” to the state of Texas on or before Tuesday. That information will not immediately be made public unless both parties agree to it.

But both sides in the case are scheduled to convene for a conference Wednesday to discuss a trial schedule, after which more details might be released.

Nonetheless, this means the Texas redistricting case is bound for federal court, according to Samuel Bagenstos, a professor at the University of Michigan Law School and attorney for the Justice Department’s Civil Rights Division until last month. Bagenstos cautioned that this could be a long process given that both sides are entitled to discovery and questioning under oath.

“All that’s going to take time,” Bagenstos said.

That’s a problem because candidates may start filing for offices in early November in Texas. But if the maps are not finished in time, the state Legislature might be forced to move back the primary timetable.

“Once a state decides to go to court, it loses control over the schedule,” Bagenstos added. “The rules of federal litigation kicks in.”

Texas Democrats rejoiced in the Justice Department’s announcement. Rep. Lloyd Doggett (D) is the GOP’s top target under the new lines adopted earlier this year. If they are upheld, he will likely be forced to run in a nearby heavily Hispanic district. But Doggett indicated Monday that he believes legal proceedings will change the shape of the new 35th district.

“Whether or not proposed CD 35, which contains the largest number of my current constituents, is specifically declared illegal, I believe that it may well be changed by necessary corrections to adjacent Congressional districts,” he said.