Republican Senator Thad Cochran addresses supporters during an election night celebration after defeating Tea Party challenger Chris McDaniel in a run-off election in Jackson, Mississippi, June 24, 2014. Reuters

In a closely watched election that was essentially a referendum on the tea party's power, black voters in Mississippi, a profoundly red state, managed to decide a Republican primary -- a first, and one that could presage a change in the way demographics influence party power.

The race, between incumbent Sen. Thad Cochran and state Sen. Chris McDaniel, a tea party Republican, surprised even seasoned political analysts because it showed that a marginalized Democratic Party could flex its muscle in new and unexpected ways.

Cochran, whom McDaniel criticized for being too friendly with Democrats, did not respond as might have been expected -- by assuming a more conservative posture and vociferously rejecting bipartisanship. Instead, he openly courted Democratic voters, particularly in black-majority counties. It may have been an act of desperation, but it paid off. Democrats voted for Cochran in the state’s open Republican primary, even if, as some said, they did so only because he was the lesser of two evils.

“To have a win in this way is too many things to juggle,” Marty Wiseman, formerly of the John C. Stennis Institute at Mississippi State University, told International Business Times. “Most have discounted the black vote, so to call on them and they delivered will take a few days to process.”

Since the 1980s, the Deep South has shifted from almost uniformly Democrat to solidly Republican when it comes to statewide elected offices. While the minority population in the South -- most of whom are black or Latino -- continues to rise, their political has yet to extend beyond local elected offices (Mississippi now has the most black elected officials of any state, but only one African American representative in Congress).

Byron D’Andra Orey, a political science professor at Jackson State University, told IBTimes in December that Mississippi is still a long way from seeing African Americans’ numbers put the state “in the win column” for a Democratic presidential candidate in the state legislature.

Still, political analysts say increasing minority populations in the South could point to the future of the U.S. political system, and Tuesday’s Republican primary in Mississippi could be a significant bellwether.

“Mississippi has as good, if not a better, chance to go Democratic than any other [Southern] state,” Wiseman said. “Most [of Mississippi’s African Americans] vote Democratic. Then there’s a piece of the white population that still votes Democratic in the state. If you can put all that together and get them to the polls than you have a good chance” of turning the state blue.

The Democratic vote in Mississippi was “wandering out in the wilderness” until this election, Wiseman said. For many Democrats, the Republican primary was the first time they had ever voted Republican -- and, come general election time, “a lot of them will head back to the Democratic Party in November,” he said.

The question on the minds of some political observers is whether Cochran, if he wins the general election in November, will maintain his bipartisan, biracial approach and remember the tens of thousands of new voters who helped him survive the tea party challenge. Rickey Cole, chair of the Mississippi Democratic Party, is skeptical.

“I don’t see [Cochran] changing a thing,” Cole told IBTimes. “He and his staff are part of the Mitch McConnell Republican machine. He’s going to vote with leader McConnell.”

Cochran appeared to be the perfect target for a tea party takedown: a six-term senator who ran a relatively sleepy campaign on the platform that he is an incumbent with 40 years of experience on his side.

“We did consider [the race] to be sort of the Alamo, and we knew if we were successful down here that the narrative would be a lot better heading into the fall and 2016,” Steve LaTourette, a former Ohio Republican congressman who is currently president of Main Street PAC, a group that supports moderate Republicans, including Cochran, told The Hill. “I don’t think [tea party candidates] have the ability to sneak up on people anymore.”

Already, the state is less conservative than many observers might assume. Cole said the first indication of Mississippi’s slow shift to the left -- its “watershed moment” -- came in 2011 when the state shot down an anti-abortion personhood amendment that would have dictated that life begins at fertilization.

Some analysts say the state will eventually become the first with a black majority population. At that point it will likely become solidly Democratic -- unless some Mississippi Republicans decide that Cochran's victory shows that the African-American vote can be wooed, and begin aggressively to court it.

How Democrats managed to tip the Republican primary election is rooted in Mississippi’s open primary law, which allows a voter, whether Democrat or Republican, to vote in any party’s primary, the only stipulation being that the voter must vote in the same party primary if there is a runoff. It would be illegal, for example, for Democrats who voted in the Democratic primary to switch to the Republican primary for the runoff.

In the three weeks since Mississippi’s first primary election, Cochran managed to grow his electorate by wooing Democrats in the most federally-dependent state in the U.S. with ads that highlighted his support for “our aerospace industry, shipbuilding, military bases, research and development and agricultural breakthroughs.”

Despite an aggressive campaign by Chris McDaniel, whose supporters included conservative heavyweights like Sarah Palin, Cochran’s approach worked.

According to recent polling, runoff turnout in the 24 counties with a majority black population was up almost 40 percent from the primary on June 3. In all other counties, turnout was up by less than 20 percent. In the 10 counties where Cochran’s numbers improved the most, blacks make up 69 percent or more of the population.

Cochran now faces a conservative Democratic opponent in the general election, Travis W. Childers, who served as the U.S. Representative for Mississippi's 1st congressional district from 2008 to 2011.

This month’s primaries were also the first election in which the state’s controversial voter ID law was in effect. The law require voters to present valid ID to have their vote count; if a voter shows up at the polls without an ID, they can still cast a vote, but that vote is not counted until he or she presents an ID. The voter has five days to do so from the time the initial vote is cast, so it’s too early to tell how many votes are still in limbo.

Cochran’s effort to woo black voters didn’t go unnoticed by McDaniel's tea party base, which warned that they would be scrutinizing Democratic voters who voted in the Republican primary. McDaniel has since indicated he will contest the election if irregularities are found.