AUSTIN, Texas -

A major election year in Texas has overshadowed an upcoming trial on the fate of the state's tough new voter ID law, with a judge set to determine whether it safeguards ballot integrity or discriminates against minorities by imposing a mandate that suppresses turnout.

U.S. District Judge Nelva Gonzales Ramos in Corpus Christi will begin hearing arguments Tuesday on one of the nation's most stringent voter ID measures, which Republican Gov. Rick Perry signed into law in 2011.

A ruling is unlikely before Election Day, meaning that 13.6 million registered voters in Texas would still produce a photo ID this November. That hasn't stopped Democrats from wielding the law as a campaign cudgel, particularly Wendy Davis, who has attacked Republican Attorney General Greg Abbott over his office defending the measure in court.

The Texas law requires voters to show one of six kinds of photo ID. A Texas concealed handgun license is valid while a college student's university ID is not, which opponents say shows Republicans trying to imposes obstacles on voters who typically vote Democrat.

The Justice Department is taking an aggressive role in trying to dismantle the law after the U.S. Supreme Court last year threw out a key portion of the federal Voting Rights Act, which had thwarted a flurry of recently passed voter ID measures in conservative states from taking effect.

U.S. Attorney General Eric Holder made Texas a top target after vowing to go into states to wring out whatever remaining voter protections he could.

Minority rights groups that sued Texas over the voter ID law say the Justice Department has added muscle — and money — since joining the lawsuit last year.

"It's leveled the playing field," said Joe Garza, a San Antonio-based attorney for the Mexican American Legislative Caucus. "I think the overall evidence is going to show significant impact on the minority community."

The trial is expected to last two weeks. Although Gonzales Ramos could issue an immediate ruling from the bench that could affect the November elections, attorneys believe that is unlikely.

Court battles over voter ID laws elsewhere have been mixed. In August, a federal judge in North Carolina denied efforts to stop that state's newly passed voter ID from being implemented this November. Measures in Alabama and Indiana also remain intact, while one in Wisconsin remains on hold.

Attorneys for the state argue that despite months of preparation for trial, there is no evidence that the law was designed to suppress certain voters.

"After deposing numerous state legislators and legislative staff members, and after reviewing the record of this case, DOJ is unable to identify any statement made by any Texas legislator or staffer that evinces a desire to harm racial minorities," the state wrote in a filing this month.

Free voter IDs are offered by the state, though one third of Texas' 254 counties do not have Department of Public Safety stations that can provide the cards, and opponents say voters must still pay for copies of birth certificates or other documents to obtain the ID.

Since the law took effect last summer, the agency has issued 279 voting IDs but reports receiving 1,700 inquiries.

Texas has held two elections so far since the law took effect, neither of which resulted in widespread reports of turned-away voters. Following the November 2013 elections, state elections attorneys logged fewer than half the number of complaints as they did in 2011, according to the Texas secretary of state's office.

Turnout in those off-year elections is historically low, and opponents say the real ramifications won't be seen until November.

"Some of the most far-reaching implications wouldn't be fully clear until a huge election," said Natasha Korgaonkar, an attorney for the NAACP Legal Defense Fund. "That's when we're going to see a number of voters who are vulnerable."