South likes new political landscape. Southern political leaders are putting the finishing touches on plans for Super Tuesday. They are pleased with candidates' attention to the region. But they say one thing is missing: a Democratic hopeful with widespread appeal in the South - someone like Georgia Sen. Sam Nunn (right).

The Southern regional primary - the largest event on the political calendar between now and Election Day - is still the story of the missing candidate. Republican and Democratic statehouse pols are meeting this week at the Southern Legislative Conference to take stock of their plan to turn March 8, 1988, into Super Tuesday.

The talk is wistful of two conservative Democrats not in the presidential race - former Virginia Gov. Charles Robb, who says he won't run, and Georgia Sen. Sam Nunn, who says he is leaning against running.

Aside from them, legislators here say, no Democratic candidate has managed to capture the imagination of the Southern voter.

But virtually everyone here sees the new political landscape as better than the old. Candidates from both parties are heading south, talking and listening to Southerners.

``We like the attention,'' says Mississippi State Rep. Charlie Williams (D), noting that each of the candidates has already visited at least once.

``I've had more candidates come to call in my office in the past three weeks than in the last 13 years,'' says Tom Murphy, Georgia's curmudgeonly House speaker.

``Even Pat Schroeder has been by to see me,'' he says, referring to the Colorado congresswoman who is considering a presidential bid.

Three years ago, most of the Democrats here (and 77 percent of Southern state legislators are Democrats) wanted nothing to do with their national candidate, Walter Mondale. Ronald Reagan polled more than 60 percent in many Southern states in 1984.

So the Democrats rebuilt the political landscape. They drafted plans to pool their regional clout, force the national candidates to the South, and eventually to nominate a moderately conservative Democrat, perhaps even a Southerner.

So far it's working. Fourteen Southern and border states have joined in. On March 8, three weeks after the New Hampshire primary, a region of 40 million voters, 97 media markets, and 30 percent of the delegates to each party's convention will weigh in.

But doubts and risks abound:

No Democrat has yet shown a regionwide Southern appeal that could draw Southern voters away from the Republicans.

Many in Deep South states predict that the Rev. Jesse Jackson, the most liberal candidate in the race, may win their states, thus undermining the quest for a conservative candidate.

Independent voters and many conservative Democrats may vote in the Republican primary, leaving the Democratic race to liberal activists. Republicans are seeking to cast the primaries as conservative and liberal primaries, rather than in strictly party terms.

Super Tuesday follows so closely on the heels of the Iowa caucuses and the New Hampshire primary that Southern voters may simply amplify the earlier outcomes, responding to media coverage of the winners and losers.

This is the scenario Southerners cannot abide, especially since a Sam Nunn candidacy would probably skip over Iowa and New Hampshire altogether.

Southern politicians, however, are convinced that Super Tuesday will be the most important event leading up to the election. Which party and which candidates it will favor is a harder question.

``If ever the law of unintended consequences is likely to apply,'' former Tennessee Gov. Lamar Alexander (R) noted here Monday, ``this will be the day.''

Not only is the regional primary new, but in five of the Super Tuesday states, 1988 will be the first year a primary has replaced party caucuses. In Texas, for example, the change means four to five times more Texas Democrats will participate in delegate selection, according to Jay Hakes, an aide to US Sen. Bob Graham (D) of Florida and an architect of the Super Tuesday plan.

``The Southern regional primary itself will infuse millions of new voters into the process without any further effort,'' he adds.

Another wild card is that eight of the 14 Southern Super Tuesday states hold open primaries, meaning conservative Democrats are free to vote in the GOP primary. Both parties are figuring that whichever primary voters choose, they are more likely to support that party's candidate in November.

William McInturff, a consultant to the Republican National Committee, sees a GOP edge in another part of Super Tuesday mechanics. While most of the Democratic primaries assign delegates in proportion to the vote a candidate polls, nine of 14 GOP primaries are winner-take-all.

So the Republicans are more likely to take a clear-cut winner out of Super Tuesday to unify around.

Both parties badly want a large turnout in their own primaries. The Democrats hope to pull conservatives back to the fold - at least a portion of them. Republicans want to establish a legitimate two-party South.

Both parties are minority parties in the South, says political scientist Merle Black. Therefore, they each need to unite their ranks and reach beyond them to win elections.

For the Democrats, the answer lies with the missing men. ``Robb is the first choice with a lot of people and the second choice for everybody,'' says Representative Williams of Mississippi.

``We're waiting to see what Sam Nunn's going to do,'' Georgia State Rep. Henry Reaves says.