According to the law, North Dakotans must have IDs with a residential address in order to vote. Historically, Native Americans have often relied on post office boxes—but these are no longer an adequate form of proof of residence. The law could therefore prevent many of the approximately 30,000 Native Americans living in North Dakota from voting.

In North Dakota, residents are not required to register before voting. Therefore, tribes are working overtime to assign addresses and issue identification that meets the law’s requirements ahead of Election Day on Nov. 6.

In several instances, the tribes are waiving the fees usually associated with ID cards and helping residents either determine or create an address. The Standing Rock tribe, for example, has set up a hotline and is able to create new IDs instantly. They’ve also launched a GoFundMe to help pay for their efforts to transport tribal members to the polls, pay for new ID cards, and file voting paperwork, which had raised more than $178,000 in the first 12 days.

Four Directions, a Native American voting rights group, has similarly started a Crowdpac to help get Native Americans to the polls on Election Day, raising more than $75,000 as of Wednesday.

According to data acquired by NBC News, at least 1,360 people have already gotten new IDs thus far. Many Native Americans are going door-to-door to provide information about the new voting requirements and encourage others to vote.

While supporters of the new law argue that it is intended to prevent voter fraud, many Native Americans have seen it as an attempt at voter suppression. Their disenfranchisement could also have consequences for Democratic incumbent Sen. Heidi Heitkamp, who won her seat by just 3,000 votes in 2012. Native Americans overwhelmingly vote Democrat, and in a state with just 750,000 residents, without their vote, Heitkamp’s already close re-election bid could fail.