As they have for years, claims of voter suppression continue to be made by Democrats, including U.S. Rep. Gwen Moore and U.S. Sen. Tammy Baldwin of Wisconsin.

When President Donald Trump signed an order to create a commission to study voter fraud, Moore attacked its vice chairman as having "led numerous voter suppression initiatives against minorities."

Five days later, on May 17, 2017, Baldwin made this declaration on Twitter:

Voter turnout in 2016 was reduced by approx. 200,000 votes because of WI’s photo ID laws.

We’ve rated Mostly True a claim by TV show host John Oliver that in Sauk City, Wis., the office that provides identification for voting was open only four days in 2016.

But on a claim closer to Baldwin’s, we rated False tweets that said "300,000 voters were turned away" by Wisconsin’s voter ID law in the 2016 presidential election. A federal judge had determined that some 300,000 registered voters lacked the necessary ID to vote, but there was no evidence that anywhere near that number of people were turned away from the polls.

What about Baldwin’s claim?

What voter ID is about

Thirty-four states have laws requesting or requiring voters to show some form of identification at the polls, according to the nonprofit National Conference of State Legislatures.

Wisconsin is among seven states that have a strict requirement -- voters without acceptable identification must vote on a provisional ballot and also take additional steps after election day for their vote to be counted.

As the group puts it:

Proponents see increasing requirements for identification as a way to prevent in-person voter impersonation and increase public confidence in the election process. Opponents say there is little fraud of this kind, and the burden on voters unduly restricts the right to vote and imposes unnecessary costs and administrative burdens on elections administrators.

A few days before Baldwin made her statement, the Associated Press reported on examples of Wisconsin residents who said they couldn’t get the ID they needed to vote in the 2016 presidential election -- the first presidential contest in which the state’s ID law was in place.

But the story said it is unknown how many people did not vote because they didn’t have proper identification.

Baldwin’s evidence

To back Baldwin’s claim, her campaign cited a report issued two weeks earlier. It’s worth noting who was behind it.

The report was commissioned by Priorities USA Action, a political action committee that supported Barack Obama and Hillary Clinton and describes itself as a "voter-centric progressive advocacy organization" that is "committed to standing up to the Trump administration and its allies." The group says its "voter suppression analysis" is part of an effort to "glean lessons that can be applied to strengthen Democrats in elections in 2018, 2020 and beyond."

The report was conducted by CIVIS USA, a Chicago firm founded by the chief analytics officer of the 2012 Obama campaign team.

The report compares the 2012 and 2016 elections. It says that on average, turnout increased 1.3 percent in states in which there was no change to voter ID laws, but decreased 3.3 percent in Wisconsin.

The report concludes that had there been no voter ID in Wisconsin, turnout would have risen by 1.3 percent -- or 200,000 voters -- over the 2012 total.

(Although it doesn’t affect the rating of Baldwin’s claim, the report also argues, based on other data, that the 200,000 people it refers to "would have been more Democratic," and notes that Clinton lost to Trump in Wisconsin by about 20,000 votes.)

Ignoring other factors

Roughly 3 million votes were cast in each of the last three presidential elections in Wisconsin. As we’ve noted, the 2016 turnout was lower than 2012, when Obama won reelection and there was no voter ID requirement.

On the other hand, the 2016 turnout was higher than when Obama was first elected in 2008 and, again, there was no voter ID law.

More importantly, according to experts, the methodology of the report Baldwin cites is lacking. Put simply: The voter ID requirement undoubtedly prevented or discouraged some people from voting. But the report attributes all of the decrease in turnout to the ID law, when there are many other reasons that could also explain it, including a lack of enthusiasm for Clinton or Trump, or perhaps a belief that Trump couldn’t win Wisconsin.

"The story is getting picked up by Democrats and left-leaning smart people across social media because it confirms what they already think," University of California, Irvine law and political science professor Rick Hasen wrote on his election law blog. "But there is reason for considerable caution about this study, which is at odds with what other studies of the effect of Wisconsin’s voter ID has found. There are questions about the study’s methodology being raised by people who know their stuff."

Yale University political science professor Eitan Hersh tweeted: "No offense, but this is something that is going to be shared hundreds of times and does not meet acceptable evidence standards."

Barry Burden, director of the Elections Research Center at the University of Wisconsin-Madison, told us there’s simply no way to put a number on how many people didn’t vote because of the voter ID law.

Bucknell University political science professor Lindsay Nielson has done research finding that voter ID laws lower minority turnout and benefit the Republican Party. But as for the voter turnout decline in Wisconsin, "there could be a multitude of other reasons" why voters stayed home, she told us. "Voter ID laws could very well have been suppressing voter turnout in Wisconsin," but "we just can’t say it’s 200,000 people. We need a lot more research before we can draw that conclusion."

Baldwin campaign spokesman Scott Spector responded by saying "there is no reason to question the (CIVIS) study or believe other factors were involved," because of one of the findings in a September 2014 by the nonpartisan U.S. Government Accountability Office. But that finding didn't look at the 2016 election and involved two different states.

The GAO found turnout between the 2008 and 2012 elections declined more in Kansas and Tennessee than in states that did not change voter ID requirements -- by an estimated 1.9 to 2.2 percentage points more in Kansas and 2.2 to 3.2 percentage points more in Tennessee — and the results "were attributable to changes in those two states’ voter ID requirements."

Our rating

Baldwin says: "Voter turnout in 2016 was reduced by approx. 200,000 votes because of WI’s photo ID laws."

A report she cites from a Democratic candidate-supporting group says a decline in voter turnout between the 2012 and 2016 presidential elections in Wisconsin was entirely due to the state’s new photo identification requirement for voting.

But experts say that while photo ID requirements reduces turnout to some extent, they question the methodology of the report and say there is no way to put a number on how many people in Wisconsin didn’t vote because of the ID requirement.

We rate Baldwin’s statement Mostly False.