A new study on the effect of voter ID laws shows they tend to decrease turnout among minority voters.
Looking at data from elections between 2006 and 2014 in states where people can't vote without photo identification, as well as data about minority voter participation from those places, researchers from the University of California at San Diego, Michigan State University and Bucknell University found that minority participation was lower in states that had strict voter ID laws.
"Hispanics are affected the most: Turnout is 7.1 percentage points lower in general elections and 5.3 points lower in primaries in strict ID states than it is in other states," the researchers wrote in The Washington Post. "Strict ID laws mean lower African American, Asian American and multiracial American turnout as well. White turnout is largely unaffected."
In states without strict voter ID laws, the gap between Hispanic and white voters tends to be 4.9 percent, according to the study. But in states with strict voter ID laws, the gap increases to 13.2 percent.
The gap between black and white voters grows from a 2.5 percent difference to 11.6 percent, in favor of white voters.
Because minority voters tend to vote Democrat, the result is a larger voter gap in favor of Republicans.
"All else equal, when strict ID laws are instituted, the turnout gap between Republicans and Democrats in primary contests more than doubles from 4.3 points to 9.8 points," the researchers wrote. "Likewise, the turnout gap between conservative and liberal voters more than doubles from 7.7 to 20.4 points."
Other studies have shown similar results.
In 2014, the Government Accountability Office looked at the effect of strict voter ID laws implemented in Kansas and Tennessee after 2008 but before 2012, and compared them to four states that did not implement similar laws during that time.
In Kansas and Tennessee, voter participation dropped by 3 percent.
"GAO’s analysis suggests that the turnout decreases in Kansas and Tennessee beyond decreases in the comparison states were attributable to changes in those two states’ voter ID requirements," the report said, according to The Associated Press.
Among black voters, the drop was 4 percent, compared to whites, which fell 2 percent.