Texas cannot proceed with elections under new redistricting maps without a trial, a Washington-based federal court ruled Tuesday, saying the state used an inadequate analysis to determine whether new districts discriminate against minorities.

In a brief ruling, the court agreed with the U.S. Department of Justice that the GOP-led Legislature used an improper standard for measuring minority voting strength. The order clears the way for a trial and all but guarantees the 2012 elections will be conducted with temporary, court-drawn maps.

The temporary maps, being drawn by a San Antonio court, are expected to boost Democratic efforts to regain control over Congress. That's because the maps will likely protect minority seats and provide a lifeline to at least one Democratic incumbent who had been imperiled.

The San Antonio court, considering a parallel legal fight over the maps, already has pushed back the start of the candidate filing period to Nov. 28.

The legal fight centers around a requirement in the 1965 federal Voting Rights Act that certain states with a history of discrimination, including Texas, be granted "preclearance" before changes in voting practices can be enacted.

The legal standard is whether proposed changes have the purpose or effect of diminishing voting rights based on race or color.

The Justice Department contends Texas' legislative and congressional maps are retrogressive, meaning minority voters' ability to elect their candidates of choice is diminished.