Look south. Look to Georgia and Alabama - and maybe Florida. Then look north, especially to Massachusetts. That's where black voters will have their first major impact in the 1984 presidential primaries. And that's where Jesse L. Jackson will focus his race for the White House.
Mr. Jackson made it official over the weekend. He's running, even though many black leaders - including such prominent figures as Coretta Scott King and Benjamin Hooks - have refused to support him.
Yet Jackson's effort could be very important for Democratic politics. Some say it could even determine who wins the party's presidential nomination. In brief, the impact is expected to be this:
For Walter F. Mondale, the front-runner, a minus. Mr. Mondale is strong among blacks. Jackson will divide his support.
For John Glenn, close on Mondale's heels, a plus. Senator Glenn is strongest with middle-roaders, much weaker among blacks.
Jackson, a protege of slain civil rights leader Martin Luther King Jr., will formally announce his campaign at a press conference on Thursday.
There are several views of his coming campaign. A number of black officials in interviews during the past week told the Monitor that they worry about Jackson as a spokesman for all blacks. They argue that his campaign is less for blacks and more for himself.
Jackson and his aides argue just the reverse. While he has little prospect of winning the nomination, they say that he will generate tremendous excitement in the black community, especially among younger black voters.
This could could have two effects, they say. It will result in more blacks being elected to state and local offices. And it will force both the Republican and Democratic candidates for president to address issues of greatest import to blacks.
Then there's the more immediate effect on the primaries.
A top Mondale aide, told that Jackson had decided to run, responded only with a curt ''So be it!'' There is little doubt in either the Mondale or Glenn camps how important Jackson could be.
To understand this, one needs to look at the numbers.
Mondale has been the front-runner for the Democratic nomination since the race began. But in recent months, John Glenn has closed the gap between them to about 10 points.
The Democratic candidates will first clash in Iowa during statewide caucuses on Feb. 27. The New Hampshire primary follows on March 6. Black voters will have little impact on either contest.
Then follows what may be the most important day of the primary season - March 13, ''Super Tuesday.'' There are five state primaries and four state caucuses that day. Mondale must do well to remain the front-runner.
But the geography of that day makes it difficult. Three of the primaries are in the South - in Georgia, Alabama, and Florida - where liberals like Mondale seldom do well. Mondale needs the black votes there to shore up his standing. Now that vote will be divided.
And what if Jackson's campaign results in a moderate like Glenn being nominated? ''We don't see that as a valid concern,'' a Jackson associate says.