(CNN) As in every recent Democrat primary race, the 2020 contest will begin in two virtually all-white states, with the Iowa caucus and New Hampshire primary in early February. But after that the next month of the primary calendar is dominated by states across the Sun Belt where non-white voters comprise a large share, and often an absolute majority, of the electorate.

This decisive turn toward diversity, reinforced by California's decision to move up its primary to Super Tuesday, represents a potentially critical new wrinkle in the nomination process. The pivot begins with Nevada and South Carolina, where contests will be held in the second half of February. The tilt toward diversity then explodes in early March when big Sun Belt states from Florida, North Carolina and Virginia in the southeast to Arizona and Texas along with California across the southwest will all crowd together on the calendar.

This concentration of highly diverse states in the contest's first stages underscores the potential influence of Hispanic, and especially African-American voters, in picking the winner from a Democratic presidential field likely to be the party's largest since at least 1976.

That could advantage the candidates best positioned to appeal to minority voters, particularly African Americans -- a list led by black Senators Kamala Harris and Cory Booker, as well as former Vice President Joe Biden, who's still considering whether to run. Cornell Belcher, a Democratic pollster who specializes in studying African-American voters, predicts that if any candidate emerges from South Carolina as the clear favorite among blacks -- as Barack Obama did in 2008 and Hillary Clinton did in 2016 -- that person will be very hard to beat for the nomination.

The question is what happens if the growing ranks of minority voters splinter among the field and fail to consolidate around any one candidate.

"If we come out of South Carolina with no candidate with a clear consolidation for the African-American vote, we are in for a long, drawn-out process," Belcher says. "It is going to be hand-to-hand combat from state to state to state."

new CNN analysis of exit poll data published last week from all of the contests in the 2008 and 2016 Democratic races found that the party's electorate is growing steadily more racially diverse, better-educated and more heavily tilted toward women. The analysis found that in the 2016 race between Hillary Clinton and Bernie Sanders, women cast nearly three-fifths of all the votes, college graduates just over half the votes, and people of color nearly two-fifths, according to the cumulative analysis by CNN polling director Jennifer Agiesta of the exit polls conducted in 27 states.

But while the influence of women in Democratic primaries is true in states all over the country, the party's deepening racial diversity is concentrated much more in states across the Sun Belt than in other areas. And those states are concentrated near the front of the primary calendar.

The race, as always, will still start in states dominated by white voters: In 2016, according to the exit polls, whites represented 91% of the Democratic caucus-goers in Iowa and 93% of the New Hampshire primary voters. But the 2020 calendar will then turn swiftly and sharply toward states with much greater diversity. In Nevada, the third contest, non-whites represented over two-fifths of the caucus-goers last time, with Latinos accounting for about half of that total, according to exit polls. In South Carolina, which follows, African-Americans cast just over three-fifths of the ballots in 2016 and all minorities nearly two-thirds, according to exit polls.

Diverse states then dominate Super Tuesday, the big roster of contests that will vote on March 3, 2020, and the races that follow through mid-March. Through March 17, the Democratic candidates will face significant Latino populations in Texas and California on Super Tuesday and then Florida and Arizona on March 17. (These states will be critical if former San Antonio Mayor and Housing and Urban Development Secretary Julian Castro has any hope of breaking into the top tier.)

Starting on Super Tuesday, large black populations will vote through mid-March in Virginia, North Carolina, Tennessee, Alabama, Texas, Louisiana, Mississippi, Florida and Illinois. In all of these states, minorities comprised at least about two-fifths of the 2018 vote, and they reached majority status in several of them, including Alabama, Mississippi, Florida and Texas. Given the overall trends in the party, Democratic strategists consider it likely that the non-white share of the vote in virtually all of these states will be higher in 2020 than it was in 2016.

Some predominantly white states interrupt this pattern through mid-March. Vermont, Massachusetts and Oklahoma vote on Super Tuesday and on March 10 they will be followed by Michigan, Ohio and Missouri, three Midwestern states where whites cast about 70% of the 2016 votes. But even those three states feature substantial African-American electorates.

Apart from those contests, most of the states where whites represent the largest share of the primary electorate don't vote until the second half of the primary calendar. That list ranges from Wisconsin in early April to Connecticut, Rhode Island, and Pennsylvania later in the month, to Nebraska, Indiana, West Virginia, Kentucky, and Oregon in May.

This sequencing looms over the calculations of the 2020 contenders as they start to formulate their strategies. It raises the possibility that if any candidate can establish a dominant position among minority voters, especially the African-American voters critical in the Southeast states, they could establish a potentially insurmountable delegate lead as early as the first half of March.

That's roughly the formula that both Obama in 2008 and Clinton in 2016 followed to win their nomination fights. Each of them amassed overwhelming advantages among African-American voters to sweep the key Southern contests and establish an advantage in the delegate count that their rivals -- Clinton in 2008 and Bernie Sanders in 2016 -- could never overcome.

"In the terrain of Super Tuesday it's not just winning people of color, it's dominating," said Robby Mook, Clinton's 2016 campaign manager. "No one is going to dominate women -- it's not going to happen. You might do better with college-educated folks, some candidates will skew slightly female. Where there is potential for somebody to dominate is with African Americans."

That question will largely be decided by how the first four states narrow the enormous field. Democratic strategists divide sharply on whether Iowa and New Hampshire will still play their traditional role in reducing the field to just two viable candidates.

Many believe the growing amount of attention from the media, and the expanding ability to raise money online, will allow more candidates to compete effectively even if they don't finish at the very top in the first two states. New Hampshire's impact also may be diminished if the other candidates effectively concede it to the two regional favorites, Senators Sanders of Vermont and Elizabeth Warren of Massachusetts.

"I do think Iowa and New Hampshire, while they will draw tremendous amounts of attention, will be less determinative of who plays or who doesn't," says Joel Benenson, the chief pollster for Obama in 2008 and senior strategist for Clinton in 2016.

But other veteran Democrats warn that candidates write off either of the first two states at their peril. Since 1972, Bill Clinton has been the only Democrat who won the nomination without first winning either Iowa or New Hampshire, which suggests many voters quickly lose faith in the viability of candidates who don't perform well in the first two states.

For that reason, long-time Democratic strategist Robert Shrum, now the director of Unruh Institute of Politics at the University of Southern California, says its "magical thinking" for candidates to think they can effectively concede New Hampshire to Sanders and Warren and wait until South Carolina or big delegate jackpots like California and Texas on Super Tuesday to demonstrate strength.

"I don't think Californians are going to throw away their votes on someone they might happen to like if that person has not been winnowed in [by the first states]," Shrum says. "California moving up makes California more important but it certainly doesn't make Iowa and New Hampshire less important. It may make them more important." The high cost of competing across so many large states voting on Super Tuesday may also make it more difficult for any one candidate to dominate the results that day.

There's a scenario, already being contemplated by some campaign insiders, in which Iowa favors a relatively more centrist white candidate such as Biden or Minnesota Sen. Amy Klobuchar who can appeal to its large population of blue-collar whites; New Hampshire then settles the competition between Sanders and Warren for upscale white liberals; and South Carolina decides, probably between Booker and Harris, which candidate of color appears most viable heading into Super Tuesday.

That would amount to three regional brackets, successively anointing a white centrist candidate, a white liberal and a candidate of color.

One of the biggest hurdles to such a three-way race is the possibility that a candidate of color won't attract enough black voters to win South Carolina unless they first demonstrate strength among the virtually all-white electorates of Iowa and New Hampshire. It's widely believed in Democratic circles that Obama only established his decisive 2008 advantage among African-Americans in South Carolina after he proved his viability to them by first winning Iowa.

But Belcher, who polled for Obama in the state that year, vehemently disputes that conventional wisdom. "Iowa was not a silver bullet for South Carolina," Belcher says. "I push back on that real hard: it is a fundamentally racist narrative that the black people in South Carolina were waiting for the white people in Iowa to bless Barack Obama before they decided to support him."

If Belcher is right, that raises the odds that Harris or Booker might still be able to stay competitive by attracting enough black voters to capture South Carolina, even if they don't finish at the very top in Iowa or New Hampshire.

That, in turn, would increase the chances that Democrats in 2020 could see something unprecedented in the party's recent history. If Iowa, New Hampshire and South Carolina all produce different winners, Democrats could face an extended contest between three viable candidates, each drawing on one of the party's principal pools of voters: relatively more centrist working-class whites, college-educated white liberals, and the burgeoning, ideologically-diverse, population of racial minorities.