Thousands of Texans who attempted to vote by mail in the March primary were disenfranchised in the state's first election conducted under a new Republican voting law. The state’s largest counties saw a significant spike in the rates of rejected mail-in ballots, most because they did not meet the new, stricter ID requirements.

Local ballot review boards met this week to finalize mail-in ballot rejections, throwing out 18,742 mail-in ballots in just 16 of the state’s 20 counties with the most registered voters. That includes Harris County, the state's largest county, where 6,919 ballots were scrapped — all but 31 of them because of the new ID requirements. The final statewide count for rejected ballots is still unknown; counties are still reporting numbers to the Texas secretary of state’s office.

The rates of rejections range from 6% to nearly 22% in Bexar County, where almost 4,000 of the more than 18,000 people who returned mail-in ballots saw their votes discarded. In most cases, ballots were rejected for failing to comply with tighter voting rules enacted by Republicans last year that require voters to provide their driver’s license number or a partial Social Security number to vote by mail, according to rejection data collected by The Texas Tribune. A few counties’ rejection rates also included ballots that arrived past the voting deadline, but problems with the new ID requirements were the overwhelming cause for not accepting votes.

The impact of the ID requirements was particularly pronounced in several larger counties, including Harris and Bexar. Votes lost to the ID rules accounted for 99.6% of rejections in Harris County, which reported an overall rejection rate of roughly 19% among ballots that were received in time. By contrast, the county's rejection rate in the 2018 primary was .3%.