SAN DIEGO -- Researchers from the University of California, San Diego have created a new statistical model indicating that voter identification laws do what detractors claim -- reduce turnout for minorities and those on the political left.
Overall, the researchers found, strict ID laws cause a reduction in Democratic turnout by 8.8 percentage points, compared with a reduction of 3.6 percentage points for Republicans.
The study focused on the 11 states with the strictest voter ID laws, generally requiring photo identification to cast a ballot. Researchers used a large voter survey database to compare turnout in those states to those in states with lesser or no ID requirements.
Several states have passed less strict ID laws. But in 17 states including California, New York and Illinois, a more traditional honor system still applies at the ballot box.
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The ID requirements have been pushed by groups who say they want to protect the integrity of the ballot box, but critics say fraud is minimal and the real motivation is to suppress minority and liberal voters.
The report by professor Zoltan Hajnal, a UCSD political scientist, sheds no light on the motivations of lawmakers passing such requirements, but does indicate the laws have an effect on turnout.
"The analysis shows that strict identification laws have a differentially negative impact on the turnout of Hispanics, Blacks, Asian-Americans, and multi-racial Americans in primaries and general elections," the report says. "We also find that voter ID laws skew democracy toward those on the political right."
Along racial lines, the researchers found, minority voter participation dropped an average of 4.7 percentage points among self-identified Hispanics, blacks, Asian-Americans and mixed race individuals in general elections and 5.7 percentage points in primaries.
According to the research, the effect on turnout based on ideology is also pronounced.
Self-identified strong liberals tend to turn out by 7.9 percentage points less when confronted with strict identification requirements. Strong conservatives vote at a higher rate, by 4.8 percentage points, in the strict ID environment, the research indicates.
Hajnal wrote the paper with UCSD researcher Nazita Lajevardi and Lindsay Nielson of Bucknell University.
They used voter data from the Cooperative Congressional Election Studies database, maintained by Harvard University. The database contained survey results for 50,000 respondents regarding elections from 2006 to 2014.
The authors say their paper contains more recent election data -- from states with stricter laws -- than previous research that found negligible impact on voter turnout.
Their paper has been posted online and distributed among other political scientists. It has yet to withstand peer review or be chosen for publication in an academic journal, but Hajnal has been published repeatedly on matters of race and politics, in the American Journal of Political Science, Political Research Quarterly, Urban Affairs Review and elsewhere. He is the author of last year's "White Backlash: Immigration, Race, and American Politics," from Princeton University Press.
Richard Hasen, professor of law and political science at UC Irvine School of Law, cautioned against drawing conclusions from the paper, which is an outlier.
"Social science is not this kind of thing where you have one study and it's a smoking gun and that's it," Hasen said. "It's a situation where you have a ton of studies and they all point in a particular direction."
Hasen said many confounding factors and changing rules affect voter turnout.
Surveys show wide support for voter ID laws. A 2012 Pew Research Center poll found that 77 percent of registered voters support a photo ID requirement to vote.
California doesn't have a voter ID law, although conservative talk show host Elise Richmond of Palm Springs tried unsuccessfully to gather signatures to get one on the ballot in 2014.
She said the idea that certain groups don't have or are unable to obtain IDs is paternalistic and offensive. If the laws discourage voters initially, she said, they would eventually get used to the requirement and get an ID.
"In order to do anything in the U.S., you need an ID or some sort of number to identify you," she said. "How do you get your welfare checks if you don't have some sort of number?"
Richmond, and other voter ID supporters, mentioned Mexico as a model that the U.S. should follow; that nation requires a photo ID to vote.
Tony Krvaric, San Diego County Republican Party chairman, said that voter ID is a common-sense way to prevent any possible voter fraud.
Krvaric voted for the first time when he was in his native Sweden, which required him to have an ID and proof of address. When he immigrated to California, he said, he was surprised when he was only asked for his name.
"I still have that in the back of my mind," he said about voting, "that I want to prove who I am."
As far as the study's findings, Krvaric said, informing voters of the requirements is the best way to keep turnout constant. After time, he said, any reduction in turnout would even out.
"You need an ID to fly, you need an ID to drive a car, you need an ID to borrow a library book, so I think it's a common sense position," Krvaric said.
For organizations looking to boost voter participation and engagement, voter ID laws present a hurdle. Jeanne Brown, President of the San Diego League of Women Voters, said that voter ID laws create an inconvenience, resulting in lower turnout overall.
"I like to see any statistics the other side has on voter ID laws doing anything but restricting votes," she said. "There are very few cases of people trying to vote when they aren't qualified to vote."
In the UCSD study, Hispanics show the largest drop in turnout under strict voter ID laws, followed by Asian-American and mixed race individuals. White individuals showed only a small decrease.
The researchers presented the evidence with a caveat: The reduction in votes could be caused by other factors, such as strict ID states also having more rigid registration deadlines and fewer vote-by-mail options. Also, the paper says, strict voter ID laws may simply tend to pass in states that have other environmental factors intimidating minority voters.
"The effects of voter ID laws that we see here are eerily similar to the impact of measures like poll taxes, literacy tests, residency requirements, and at-large elections which were used by the white majority decades and centuries ago to help deny blacks many basic rights," the paper says. "The nature of older barriers and current voter ID laws today remain eerily similar: they were both instituted by advocates who claimed they would help to ensure the integrity and legitimacy of democracy."
Both Lajevardi and Hajnal said that Hispanics may be turning up less frequently because of a broader set of issues including controversy over immigration policies and enforcement.
Rose Conde, secretary for the League of United Latin American Citizens of the Desert, said a combination of barriers including the very process of getting an ID may explain why Hispanics are disproportionately affected by the laws.
"Sometimes it is expensive, and some people don't want to pay the fees," Conde said.
To boost participation, LULAC has been focusing on youth engagement in politics, because Conde said, they are the demographic most likely to have the proper IDs.