Texas' request to have a federal court approve new political districts without a trial was rejected.
The court agreed with the U.S. Department of Justice, saying the new districts discriminate against minorities.
The state argues the proposed congressional plan increases the number of minority districts from 8 to 10.
District boundaries are redrawn every 10 years to reflect changes in census data. The court order makes way for a trial.
The San Antonio federal court panel is considering interim maps for the 2012 election and has already pushed back the start of the candidate filing period to November 28.