AUSTIN -- A three-judge federal panel Thursday declined to block a Republican-crafted congressional redistricting map and began a trial to determine the legality of the new districts.

Amid allegations of gerrymandering and minority voter discrimination, the trial could determine the partisan makeup of the Texas congressional delegation and influence control of the U.S. House.

Lawyers for Democrats and minority groups claim the congressional map passed by the Republican-dominated Legislature is an improper gerrymander that tramples on minority voting strength for GOP partisan gain.

State lawyers counter that the Legislature intended to enhance Republican elective opportunities by busting up pockets of Democratic votes, regardless of race.

But the judges ignored pleas from Democrats and minorities to immediately block the use of the new redistricting plan without first having a trial on the map's legality.

The groups argued that the court had no jurisdiction in the case because the U.S. Department of Justice has not finished its review of the map on whether it violates the federal Voting Rights Act protections for minority voters.

Democrats also challenged the map on a claim that the Legislature did not have the authority to redistrict unless there is a new census. They also said the map is a partisan gerrymander that might be at odds with a Pennsylvania case the U.S. Supreme Court considered Wednesday.

But U.S. 5th Circuit Court of Appeals Judge Patrick Higginbotham said the court planned to try the case through next week and make a decision on legal arguments only when that is concluded.

"You're wasting your breath if you think we're going to send everybody home today," Higginbotham told one of the lawyers.

Attorney General Greg Abbott said the court's decision to move forward with a trial is a victory for the state.

"If the judges were going to decide in favor of the plaintiffs ... we wouldn't be going forward with this legal exercise," Abbott said.

Twenty-five lawyers representing the state and the various plaintiffs in the lawsuit packed the courtroom in the Homer Thornberry Judicial Building to argue the case before Higginbotham and U.S. District Judges John Ward of Marshall and Lee Rosenthal of Houston.

The audience included political operatives, reporters for state and national news organizations and Democratic U.S. Reps. Max Sandlin of Marshall, Chet Edwards of Waco and Charles Gonzalez of San Antonio. Sandlin and Edwards could lose their seats in the U.S. House if the judges uphold the map.

The map would erase a 17-15 Democratic majority in the state's congressional delegation and replace it with a possible 22-10 Republican majority after next year's election.

Because Republicans now control the House by a 12-seat margin, a gain of seven seats in Texas could offset losses in other parts of the nation.

Democrats say the case's outcome also might affect a Republican national game plan to consolidate its U.S. House majority through state-by-state redistricting to pick up seats.

The plaintiffs' core attack on the Republican plan is that it diminishes minority voting strength in violation of the federal Voting Rights Act.

"The drawers of this plan knowingly and intentionally undermined voting opportunities for minorities," American University professor Allan Lichtman told the court.

Gonzalez testified the districts Republicans drew for South Texas hurt Hispanic voters.

Gonzalez said Republican plans to solidify their hold on District 23 diminished the impact of Hispanic voters in Webb County by splitting them into two districts. He said Hispanic voting strength was not made whole by creating a new District 25 because it had a negative impact on other districts in the Lower Rio Grande Valley.

State lawyer Andy Taylor asked Gonzalez if the Legislature, by splitting Webb politically, was trying to shore up the re-election chances of District 23 U.S. Rep. Henry Bonilla, R-San Antonio.

"If you split Webb County, you are taking reliably Democratic voters out of that district," Taylor said.

Before the trial began, Jose Garza, a lawyer representing the League of United Latin American Citizens, tried to short-circuit the process by telling the court that the trial should not proceed until after the Justice Department has reviewed its legality. Justice officials have until Dec. 22 to issue a ruling.