Washington (CNN) A Supreme Court decision this week to allow the implementation of a voter ID law in North Dakota has Democrats fearing some Native Americans would be prohibited from voting.

The law requires voters to provide a form of identification that includes their legal name, current street address and date of birth. The problem, for some Native Americans, is the street address requirement. Native Americans who live on reservations or in rural areas that lack street addresses often instead use P.O. boxes.

Rates of homelessness are also higher among the Native American population. North Dakota's law allows voters to use other forms of identification, like pay stubs or utility bills.

"Why is it getting harder and harder for Native Americans to vote? This law clearly discriminates against Native Americans in North Dakota," Standing Rock Chairman Mike Faith said in a press release. "Our voices should be heard and they should be heard fairly at the polls just like all other Americans."

The court's decision came as Democratic Sen. Heidi Heitkamp's Republican challenger, Rep. Kevin Cramer, attempts to put the race away. Polls have shown him with a near double-digit lead. Republicans are also pointing to Heitkamp's vote against Brett Kavanaugh's Supreme Court confirmation in an effort to turn out conservative voters in the deep-red state that President Donald Trump won by 36 percentage points in 2016.

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