When Barack Obama carried North Carolina in 2008 and came close in 2012, it was thanks in part to a massive advantage in early voting. Now, aiming to avoid a repeat, state Republicans are waging a relentless and brazen campaign to limit early voting opportunities — all but acknowledging that lower turnout benefits the GOP.

The state is likely to be among the closest in the presidential race this fall, and it also hosts tight races for governor and senator. Any Democratic strategy for victory will rely heavily on turning out early voters.

On Monday, Gov. Pat McCrory asked the U.S. Supreme Court to put the ID requirement and the early voting cuts back into effect. The state did not challenge the restoration of same-day registration or out-of-precinct voting. If the high court declines to intervene, as looks likely, Republicans have a backup plan: Pressuring local election boards to make early voting as inconvenient as possible.

Related: North Carolina Asks Supreme Court to Block Voter ID Ruling

Early voting has become extremely popular in recent elections in North Carolina, and it's disproportionately favored by African-Americans. In 2008, over 60 percent of black voters cast their ballots early, compared to 44 percent of white voters, according to one expert analysis. In 2012, those figures rose to 64 percent and 49 percent respectively.

The first Republican effort to limit early voting came in 2013, when North Carolina Republicans passed a multi-pronged voting law that imposed an ID requirement, eliminated same-day voter registration, and cut the early voting period from 17 days to 10, among other provisions. That law was overturned by a federal appeals court last month, which found that Republicans passed the measure after receiving data showing that blacks vote early, and lack ID, at higher rates than whites.

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The appeals court’s ruling meant local election boards must now draw up new early voting schedules. Under the Republican-backed law, they’d been required to squeeze as many total hours of early voting as they’d offered in 2012 into seven fewer days. That requirement no longer exists, meaning counties can, if they choose, offer fewer total hours despite increasing the number of days on which polls are open.

Related: A Rushed Vote Draws North Carolina Into National Fight Over LGBT Rights

By law, North Carolina’s local election boards are all controlled by the party of the state’s governor, who is a Republican.

On Sunday, Dallas Woodhouse, the chair of the state GOP, emailed Republican county election board members, asking them to “make party line changes to early voting,” including reducing hours, not offering Sunday voting, and not putting polling sites on college campuses.

Woodhouse’s email was obtained by the Charlotte News & Observer. He did not respond to a request for comment from NBC News.

“Many of our folks are angry and are opposed to Sunday voting for a host of reasons including respect for voter’s religious preferences, protection of our families and allowing the fine election staff a day off, rather than forcing them to work days on end without time off,” Woodhouse wrote in the email. “Six days of voting in one week is enough. Period.”

He added: “No group of people are entitled to their own early voting site, including college students, who already have more voting options than most other citizens.”

Related: Why North Carolina's Voting Law Hits Low-Wage Workers Hardest

A day after Woodhouse’s email was sent, the elections board for Mecklenburg County, the state’s largest, voted to cut early voting hours by 238, compared to the 2012 election. The chair of the board, a Republican, had said she’s “not a fan of early voting.”

Woodhouse’s controversial email came not long after Francis De Luca, the head of a conservative North Carolina think tank with ties to a major Republican donor, similarly urged local boards to reduce early voting hours, claiming “it’s partisan politics – it’s not racial or anything.”

The election law scholar Rick Hasen wrote on Twitter Wednesday that the GOP drive to limit early voting “could put North Carolina back under federal supervision for its voting for up to ten years.” Under the Voting Rights Act, if a jurisdiction is found to have intentionally discriminated in voting, it can be required to clear all election changes with the federal government.