Republican state officials working to pass a voter photo ID law in 2011 knew that more than 500,000 of the state’s registered voters did not have the credentials needed to cast ballots under the new requirement. But they did not share that information with lawmakers rushing to pass the legislation.

Now that the bill is law, in-person voters must present one of seven specified forms of photo identification in order to have their votes counted.

A federal judge in Corpus Christi has found the law unconstitutional, but the U.S. Supreme Court has ruled that the state can leave it in place for the November election while appeals proceed.

The details about the number of voters affected emerged during the challenge to the law, and were included in the findings of U.S. District Judge Nelva Gonzales Ramos.

During the 2011 legislative struggle to pass the voter ID law, she wrote, Republican lawmakers asked the Texas secretary of state, who runs elections, and the Texas Department of Public Safety, which maintains driver’s license information, for the number of registered voters who did not have state-issued photo identification.

The answer: at least a half-million.

There was evidence, the judge wrote, that Sen. Tommy Williams asked the Texas Department of Public Safety to compare its ID databases with the list of registered voters to find out how many people would not have the most common of the photo IDs required by the law. No match was done to see how many people did not have other acceptable IDs. “That database match was performed by the SOS, but the results showing 504,000 to 844,000 voters being without Texas photo ID were not released to the Legislature.”

Gonzales Ramos sourced that finding in a footnote, noting that in a deposition, Williams, a Republican from The Woodlands who has since left the state Senate, said he requested that information and then did not share it with fellow lawmakers.

That many voters could make a real difference. Rick Perry, a Republican, beat Bill White, a Democrat, handily in the 2010 race for governor, winning by almost 13 percentage points. That was a difference of 631,086 votes. Earlier this month, the secretary of state announced that a record 14 million Texans are registered to vote in the coming general election. Using that office’s 2011 estimate, it is no stretch to think that 3.6 percent to 6 percent of current registered voters do not have the photo IDs now required to cast a ballot.

State Sen. Rodney Ellis, Democrat of Houston, testified in the federal case that he asked the secretary of state for the information and never received it. But not everyone was uninformed. Citing depositions from Lt. Gov. David Dewhurst and Ann McGeehan, an elections official with the secretary of state at the time, the judge wrote, “Lt. Gov. Dewhurst was aware of the no-match list results showing 678,000 to 844,000 voters being potentially disenfranchised.”

A spokesman for Dewhurst, Andrew Barlow, said the lieutenant governor was aware of the results when he gave his deposition, but not when the Legislature was debating the bill.

The no-match list was not enough, apparently, to prompt voter ID proponents to revisit the measure during the 2013 legislative session. So far, three statewide elections have been held using the new voter ID requirements, without clear evidence that it affected either turnout or outcomes: a vote on constitutional amendments in November 2013, and the party primaries and runoffs earlier this year.

The fate of the legislation was never in question in 2011. On the final vote, only 47 of 150 House members and 12 of 31 senators voted against it. Litigation started immediately and led to the ruling this month that the law is unconstitutional; has “an impermissible discriminatory effect against Hispanics and African-Americans; and was imposed with an unconstitutional discriminatory purpose.” The judge capped that by saying the law acts as an unconstitutional poll tax.

The Republicans who wanted the law won in the Legislature, and the Democrats who did not want it won the first round in court. However, the Supreme Court left the law in place, apparently wanting to avoid any disruption in this year’s elections.

At the moment, that leaves a legal contradiction: The law is both unconstitutional and in force.