The Democratic Party's deep commitment to fairness requires that, in designing its nominating process, every faction have its turn to foul up once.

The reformers' rules in 1972 gave the Democrats George McGovern; the regulars' rewrite in 1976 produced Jimmy Carter (of whom they had not previously heard); the congressional wing asserted its prerogatives in 1984 and came up with Walter Mondale. And now the South is saying, "Stand back, boys, we'll show you how to do it right."

The main topic at last weekend's Democratic National Committee meeting was the southern "super-primary," which is beginning to look like a 1988 reality. Since the scheme of moving most Dixie delegate selection into the second week of March was first broached last December, it has spread like kudzu.

Kentucky has voted to join Florida, Georgia and Alabama in a March 8, 1988, primary. Bills setting caucuses or primaries the same week have passed one house of the legislatures in Maryland, Mississippi, Missouri, Oklahoma and Tennessee and are awaiting the governor's signature in Virginia. Texas is expected to sign up in 1987.

The goal of the governors and legislators promoting the scheme is not to get the voting done before the chiggers start to bite. Their strategy is to amass such a bounty of southern delegate votes in one week that the contenders will shape their early campaigns and messages to Dixie sensibilities. They hope to ensure that this time the Democratic ticket is led by someone who can be sold in the South in November -- a moderate, definitely, and a southerner, ideally.

The chances that it will work out that way are not terrific.

Their dream will be realized if -- but only if -- a southern moderate can do in 1988 what Carter did in 1976: sneak off with a plurality victory over a large field of liberals in Iowa and New Hampshire. New Hamsphire is scheduled to hold its 1988 primary on March 1; the Iowa caucuses come a few days earlier. If a Chuck Robb of Virginia or a Sam Nunn of Georgia can win New Hampshire, the availability a week later of a huge bloc of votes in his native region might make him unstoppable.

But the leverage will still be with New Hampshire and Iowa. Bert Lance, the former Georgia Democratic chairman, said the other day that the southern primary means "Iowa and New Hampshire (will) no longer tell us who the nominee is going to be." That's wrong. None of the advisers to 1988 hopefuls with whom I have talked thinks for a moment his man can skip the Iowa caucuses or the New Hampshire primary and start his campaign in the South.

We know from history that the winner of New Hampshire -- whether a moderate or a liberal -- gets a tremendous temporary boost in publicity and public support across the country, including the South. The bigger the bloc of votes available the next Tuesday, the larger the premium for winning New Hampshire.

It's a fallacy to think that southern primaries are inherently tough for liberals. Between them, Mondale and Jesse Jackson, the two most liberal Democrats running in 1984, won anywhere from 54 to 66 percent of the votes in every southern primary except Florida's (Florida was won by Gary Hart -- strictly off his New Hampshire momentum).

Lee Atwater, George Bush's South Carolina- born strategist, thinks the Democrats in the South "aren't calculating the odds right, because they've forgotten we (Republicans) will have a contest for our nomination in 1988." Atwater notes that the power of blacks and liberals in the 1988 Democratic primaries in Dixie will be enhanced if conservative whites are drawn off in large numbers into the GOP primary.

That is the likelihood. In eight southern states -- Alabama, Arkansas, Georgia, Mississippi, South Carolina, Tennessee, Texas and Virginia -- there is no party registration. Moderate and conservative whites who have twice voted overwhelmingly for Ronald Reagan may well be tempted to seek his successor in the Republican primary contest. If they desert the Democratic primary in droves, they automatically dim the chances of a comeback by a moderate Dixie Democrat who has been defeated in New Hampshire.

Donald Fowler, the South Carolinian who headed the latest Democratic Party rules revision, is skeptical of the rush to a regional primary -- for exactly the reason Atwater suggests. "Take a look at who turns out," he suggests.

The best comment on the whole Democratic scheme comes from a Republican, North Carolina Gov. Jim Martin. "I'm almost afraid to talk about it too much in public," he said, "for fear they (the Democrats) won't do it. I feel like Brer Rabbit and the briar patch.

"I think it's wonderful and noble that these Democrats want to improve their party by increasing the southern influence in their process. But I think it's even more wonderful that they want to bring all their candidates down into our states.

"By the time they have paraded Mario Cuomo and Gary Hart and Jesse Jackson and the rest of their roster through the South . . . I think the election will be about over."