AUSTIN — A national advocacy group that refuses to disclose its donors is running television ads in Houston, San Antonio and other Texas cities opposing a contentious bill that would increase the penalties for voting crimes.

Under the sweeping legislation, making false statements on a voter registration form would be treated as a state jail felony, punishable with up to two years in prison and fines of up to $10,000. In addition, people could face a misdemeanor charge for impeding voters’ access to the polls by blocking a walkway, road or sidewalk within 500 feet of the entrance — a distance substantially longer than a football field.

Named a priority by Lt. Gov. Dan Patrick, the bill has already cleared the Republican-led Senate and is scheduled to go before the House Elections Committee on Wednesday. Its author, Republican Sen. Bryan Hughes of Mineola, says SB 9 is needed to enhance election security by ensuring a paper voting trail and increasing penalties for voting crimes. But civil rights groups say it’s the latest attempt to suppress the vote by threatening voters with jail for mistakes on paperwork, and putting up more red tape.

The ads by Secure Democracy take issue with one provision of the bill that would allow partisan poll watchers to observe voters who cast a ballot with assistance from someone who isn’t a family member. The poll watcher would also be allowed to examine the ballot before it is cast “to determine whether it is prepared in accordance with the voter’s wishes,” the bill says.

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The bill is “attacking really some of the most vulnerable members of society, the elderly and disabled voters, under the guise of security,” said Colin Weaver, one of Secure Democracy’s co-founders. Weaver declined to name the group’s other founders or its financial donors, but he said the ad buy will be more than $100,000 and cover media markets in major metropolitan areas. Secure Democracy formed as a nonprofit in 2017, Weaver said, and has been active in states such as New Hampshire and Tennessee, opposing efforts that would tighten voter eligibility requirements.

Hughes, who was unaware of the ad, takes issue with Secure Democracy’s characterization.

“This is to make sure the person in there with them is really helping them,” he said. “The secret ballot has already been violated. This is to make sure that it’s the voter who is casting the vote.”

In addition to those changes, the bill would also give the Texas attorney general’s office access to the state’s voter registration list. And it would allow the secretary of state’s office to share voter social security numbers and dates of birth with other states to help prevent duplicate registrations, the bill says.

Both Attorney General Ken Paxton and Secretary of State David Whitley have come under scrutiny this year after the state’s bungled attempt to purge suspected non-citizens from Texas voter rolls. Whitley released numbers in late January indicating the office had identified over 95,000 suspected noncitizens on the state’s voter rolls. Paxton tweeted the numbers and proclaimed “VOTER FRAUD ALERT.” Within days, however, county election officials charged with vetting the list identified tens-of-thousands of U.S. citizens who had been wrongly flagged. Civil rights groups sued and the state recently settled the lawsuit by agreeing to halt the attempted voter purge.