For years, Augusta, Georgia, has held its local elections in November, when turnout is high. But last year, state Republicans changed the election date to July, when far fewer blacks make it to the polls.

The effort was blocked under the Voting Rights Act (VRA) by the federal government, which cited the harm that the change would do to minorities. But now that the Supreme Court has badly weakened the landmark civil rights law, the move looks to be back on. The city’s African-Americans say they know what’s behind it.

“It’s a maneuver to suppress our voting participation,” Dr. Charles Smith, the president of Augusta’s NACCP branch, told msnbc.

The dispute is flaring at a time when Georgia, long deep-red, is becoming increasingly politically competitive, and Democrats have nominated two candidates with famous names for high-profile statewide races next year.

Voting rights experts say the events in Augusta may be a sign of what’s to come—or even of what’s already happening. In June, the Supreme Court invalidated Section 5 of the VRA, which had required certain jurisdictions, mostly in the south, to submit election changes to the federal government to ensure they didn’t harm minority voters. Since then, harsh voting restrictions put in place by several southern states have generated national news coverage—Texas’ voter ID law and North Carolina’s sweeping voting bill most prominent among them. But most of the changes stopped by Section 5 weren’t statewide laws. Instead, they were measures adopted at the local or county level.

“It’s school boards, and county commissions, and city councils, and water districts, and police juries,” Julie Fernandes, a former top voting-rights official at the Justice Department, said last week at a panel on voting rights. “It’s all the stuff that really, really, really matters to folks all over the country, where they live.”

So it’s no surprise that since the high court’s ruling, smaller jurisdictions from Georgia to Arizona are moving to change election rules in ways that undermine hard-won minority political power. Donita Judge, a staff attorney with the Advancement Project, a civil-rights organization, said these kind of local election changes deserve more focused attention.

“In many ways, those type of elections are the ones that really impact you day-to-day,” Judge told msnbc. “We have to keep our eyes on those areas also.”

In Augusta, a city with a troubled history of race bias in elections, conservatives reached back over a century to unearth a tactic that was used to keep blacks from the polls during Jim Crow: changing the date of elections.

Last year, Rep. Barbara Sims, a Republican who represents the area, pushed a law through Georgia’s GOP-controlled legislature that applied only to Augusta. Against the clear wishes of the city council, the law moved the city’s elections for mayor and city council from the day of the general election in November to the day of the primaries in July.

Sims said at the time the goal was to establish uniformity with other non-partisan local elections in the state, which had been moved to July under previous legislation that applied only to counties, not cities.

But local Democrats and minorities saw the law as a bid to lower turnout among blacks, who usually vote in much higher numbers in November general elections, which tend to have a high profile, than they do in less-publicized primaries.

That figures to be particularly true next year, when two highly anticipated statewide races are likely to draw black voters to the polls in the fall. Jimmy Carter’s grandson, Jason Carter, is challenging the incumbent Republican governor, Nathan Deal. And Michelle Nunn, the daughter of longtime Georgia senator Sam Nunn, is running for an open U.S. Senate seat that could help determine control of the chamber. Adding to the intensity of the partisan conflict, there’s growing talk that, as with Texas, demographic trends could slowly be turning Georgia blue.

A close look at turnout numbers bears out the concern that the change in Augusta will hurt minorities. Seventy-five percent of Augusta blacks voted in the November 2012 general election, while just 33% did so in the July primaries. By comparison, 73% of whites voted in November, and 43% voted in July, according to U.S. Justice Department figures. 2010 showed a similar pattern. In other words, moving the election from November to July would likely lead to a sharp decline in voting among both blacks and whites—in itself an argument against the change—but the drop-off would be bigger among blacks.

Turnout rates are often the key factor in election results in Augusta, where blacks make up a slim majority of the population. If black and white turnout is roughly equal, as it tends to be in November, black and black-supported candidates can win. If whites turn out at a higher rate, as they usually do in July, white conservative candidates get a major boost.

Among the candidates likely to be harmed by the election change is state Sen. Hardie Davis, an African-American Democrat running for mayor.

Citing those turnout numbers, the Justice Department blocked the change last December under Section 5 of the Voting Rights Act, finding that it would reduce the political power of Augusta’s blacks.

“Although the change affects only Augusta-Richmond, it does not appear to have been requested by local citizens or officials,” a Justice Department official wrote in a letter to Georgia officials. “There is no evidence that the legislation’s sponsors informed, much less sought the views of the local delegation, minority legislators, or local officials about the change at any point.”

This wasn’t the first time the Feds had stepped in to block changes that they concluded would hurt Augusta’s black citizens. As the Justice Department noted, there was even a previous effort in Augusta to move the election from November to July, blocked by DoJ in 1989.

But then came the Supreme Court’s ruling in Shelby County v. Holder. Deciding that the South had made enough progress on race relations since the 1960s, the court declared the formula behind Section 5 unconstitutional, neutering the provision unless Congress acts.

That led the office of Georgia’s attorney general to conclude that the move to July could go forward. The secretary of state still needs to rule on the issue, and lawsuits are expected whatever the outcome. But it currently looks more likely than not that the election will be moved.

If it is, Augusta would join a growing list of places where conservatives have taken advantage of the Shelby County ruling to institute changes that diminish the political influence of local blacks and Hispanics.

As msnbc reported last month, Shelby gave a key boost to a group of white conservatives in Beaumont, Texas, who have been pushing to oust the black majority of the local school board. Not far away in the city of Pasadena, just east of Houston, Shelby also emboldened conservatives to pass a voter initiative this month that changes the way council districts are drawn up, likely reducing the council’s Hispanic representation. Galveston County, also in southeast Texas, seized on Shelby to push forward in August with a plan that would reduce the number of minority justices of the peace, a version of which had been blocked under Section 5 last year. And Arizona is now moving forward with a plan to add two at-large members to the district community college board for Maricopa County, which had been blocked under Section 5 because it would dilute minority representation on the board.

Those cases may just be the tip of the iceberg. Without Section 5’s preclearance requirement, there’s no longer an effective way for national voting-rights advocates and the federal government to find out about ground-level changes.

“We, and I’m sure the Department of Justice as well, are all trying to figure out how we’re going to learn about those kinds of changes at the local level now,” Dale Ho, the director of the ACLU’s voting-rights project, told msnbc. “I just have a hard time believing this is the only thing happening out there. But right now we don’t know.”