One In Six Eligible Voters Has A Disability And it’s harder for them to vote because of it.

Of all the insults Donald Trump has lobbed during the 2016 campaign, one has risen to the top: his mocking of a reporter with disabilities at a rally in Florida last fall. (Trump has denied he was mocking the reporter.) A Bloomberg poll showed voters found that moment more disturbing than any other, including his attacks on a Muslim soldier’s parents in July.

Hillary Clinton’s campaign and supporters have jumped on that moment, hoping to rally voters with disabilities and their families to her cause. Footage of Trump’s comment has appeared in Democratic attack ads, and Clinton has staked out support for ending a loophole that allows companies to pay disabled workers less than the minimum wage. She also issued a plan to support children and adults with autism.

“Four years ago the word ‘disability’ was basically not mentioned at either political convention,” said Jennifer Lazslo Mizrahi, a former Democratic strategist and the president of RespectAbility, a disability rights advocacy group. “This year, a woman in a wheelchair spoke in a prime-time slot during the Democratic convention.”

The number of eligible voters with disabilities is growing faster than the number of eligible voters without disabilities. A set of projections from two Rutgers professors show that approximately one-sixth of November’s electorate will be comprised of people with disabilities. They total 34.6 million people in all, a 10.8 percent increase since 2008. The number of eligible voters without disabilities, meanwhile, has grown by only 8.5 percent.

For years, their growing numbers have led disability rights activists to claim that voters with disabilities are a “sleeping giant” that could, one day, decide national elections. But politicians can’t count on voters with disabilities as a voting bloc in the way that they can with so many other demographics. People with disabilities tend to support Republicans and Democrats in fairly equal numbers, which complicates efforts to tailor political messages to them (and compounds their appeal as a potential swing demographic). And people with disabilities are substantially less likely to vote, in part because they face significant challenges at polling places. So what does all that mean for politicians trying to reach them?

Until now, neither party has chosen to make political hay out of disability rights; the Americans with Disabilities Act of 1990 and a set of amendments to the law in 2008 were both passed with overwhelming bipartisan support and signed by Republican presidents. Lisa Schur, a political scientist at Rutgers and one of the co-authors of the projections, said that several powerful demographic factors help explain why people with disabilities are not a political force. The first is the group’s diversity: the umbrella term “people with disabilities” actually refers to people with six distinct kinds of disability.

NUMBER OF ELIGIBLE VOTERS TYPE OF DISABILITY 2008 2012 2016 PERCENT CHANGE 2008-16 Any disability 31.9m 33.1m 35.4m +10.8% Mobility impairment 18.1 18.9 20.2 +11.2 Difficulty going outside alone 12.4 12.9 13.6 +9.7 Cognitive impairment 11.0 11.6 12.2 +11.6 Hearing impairment 9.6 9.7 10.6 +10.0 Difficulty with self-care 6.5 6.9 7.4 +14.9 Visual impairment 5.9 5.7 6.3 +6.1 Prevalence of difference types of disability 2016 numbers are census projections. Source: U.S. CENSUS BUREAU

Although people with disabilities represent a large group as a whole, that’s often not how they think about themselves. “Someone who’s blind has similar barriers to employment as someone who’s autistic, but we tend to associate only by our particular disability,” said Mizrahi.

And people with disabilities must grapple with a host of social barriers and limitations that all contribute to their low turnout on Election Day:

People with disabilities are substantially more likely to live in poverty than people without disabilities, and low-income voters are less likely to vote.

Because they’re more likely to be single, people with disabilities are more prone to a sense of social isolation and political apathy, said Douglas Kruse, an economist at Rutgers and the other co-author of the projections.

People with disabilities tend to be older than the general population, an attribute that’s usually associated with higher political participation. But the older people’s tendency to vote is canceled out by the lower levels of education for people with disabilities, an attribute that’s associated with lower voter turnout, according to Kruse.

BY… SHARE WITH DISABILITIES Education level No college degree 18.6% College degree 8.8 Marital status Single* 18.1 Married 13.3 Family income <$25,000 21.8 $25,000-49,999 12.0 $50,000-99,999 7.9 $100,000+ 6.2 Eligible voters with disabilities, 2014 *Includes people who have never been married, are married but separated, are divorced or are widowed. Source: U.S. CENSUS BUREAU

In previous research, Schur estimated that the turnout gap between people with disabilities and people without disabilities is close to 12 percentage points, which amounts to about three million voters. Despite the passage of several laws designed to make polling places more accessible, the Government Accountability Office reported in 2008 that 73 percent of polling places had at least one impediment to people with disabilities. A survey conducted after the 2012 election found that 30 percent of people with disabilities reported difficulty in voting, compared with 8 percent of people without disabilities. The turnout gap in 2012 was largest for people with cognitive impairments and smallest among people with visual impairments.

SHARE EXPERIENCING DIFFICULTY DIFFICULTY WITH DISABILITY WITHOUT DISABILITY Reading or seeing ballot 12% 1% Understanding how to vote or use voting equipment 10 1 Waiting in line 8 4 Finding or getting to polling place 6 2 Writing on the ballot 5 0 Getting inside polling place (e.g., steps) 4 0 Other type of difficulty 4 1 Communicating with election officials 2 1 Operating the voting machine 1 1 Any of the above 30 8 Voting difficulties for those with and without disabilities, 2012 Survey of 3,022 respondents (oversampled for people with disabilities) from Nov. 19, 2012, to Jan. 30, 2013 Source: Social Science Research Solutions

These modern-day inequities are rooted in a long history of discrimination and disenfranchisement, according to Rabia Belt, a legal historian at Stanford Law School. “We don’t often think about it this way, because voting is seen as such an important component of citizenship, but we don’t actually have an affirmative right to vote,” Belt said. Through the 19th century, people labeled as “lunatics” or idiots” were excluded from voting, she said, effectively disenfranchising people in socially marginal positions.

The artifacts of these laws still exist, in states where people under guardianship can be barred from voting. But often, even the basic structure of our political system is inhospitable to people who are disabled.

Kevin Truitt, an attorney at the Disability Rights Ohio, said his organization routinely fields calls from people struggling to vote on Election Day — everything from a lack of wheelchair ramps to uninformed poll workers who try to make blind voters use a paper ballot. Restrictive voter ID laws that require driver’s licenses at the polls could also disproportionately affect people with disabilities, since they are less likely to drive.

Absentee ballots are often proposed as a solution to these challenges, but a survey in 2012 found that people with disabilities prefer to cast their ballots in person. And even absentee ballots have their problems. Shelbi Hindel, an Ohio resident who is blind, voted for years by having her mother fill out her absentee ballot, effectively denying her the right to a secret vote. Now, because her polling place isn’t within walking distance, she is part of a lawsuit over the state’s unwillingness to adopt technology that would allow her to fill out her own ballot. “Voting independently is just a basic thing that I don’t think I should be asked to give up,” she said.

All of these challenges might seem to indicate that even the new publicity around disability issues might not be enough to raise the number of people with disabilities who make it to the polls. But Schur, the political scientist, pointed out that according to the new projections, more than 62 million eligible voters in this year’s electorate have a family member with a disability — and for them, Trump’s comments could be a motivating factor.

There are reasons to believe that voters with disabilities could become more politically organized soon. Older people with disabilities are substantially less likely to vote than older people without disabilities, but the participation gap vanishes among young voters.

Michelle Bishop, a voting rights specialist at the National Disability Rights Network, attributes this to a growing sense of disability pride among the people who grew up in the post-ADA era. “As we grow older, we acquire disabilities, but we don’t think of it as being part of who we are — a person is just hard of hearing, not disabled,” she said. “Increasingly, though, younger people are recognizing that this isn’t just a medical problem — it’s an identity like race or gender and that they have rights.”

Some advocates have raised concerns about whether Trump’s unwillingness to apologize for his comments or engage on disability issues will turn what has been a reliably bipartisan cause into a wedge issue. But Bishop said that although she works for a nonpartisan organization, in some cases, a little controversy can be a good thing. “When an issue is bipartisan, it sometimes means that both sides are paying lip service,” she said. “If there’s more of a political frenzy, that might mean we’re actually being taken seriously.”