(FORTUNE Magazine) – Now that Taking Jackson Seriously has been declared the main media event of the fortnight, let us sidle up to a quite serious problem about this man. It is a problem that hardly ever gets alluded to in the media except in oblique and Aesopian terms. Problem: In positioning himself on foreign policy and national security issues, Jesse Jackson never seems to take a stand that puts him in opposition to the world Soviet line. Is that serious enough for you? To be sure, Jesse has toned down or eliminated the overtly Marxist formulations that emanated from the Rainbow Coalition during his 1984 run for the nomination. He no longer goes around talking about the black population as a ''colony'' of the American empire, and he has quit characterizing his hometown (Greenville, South Carolina) as an ''occupied zone.'' He will doubtless not repeat his 1984 paeans to Cuban Communism (''Long Live Fidel Castro! . . . Long Live Che Guevara!''), delivered while visiting Havana, or denounce American policy while in Nicaragua. For the duration of the campaign, he will presumably not be giving any more interviews to Marxism Today, an organ of the British Communist party, in which he was lengthily quoted two years ago (sample: Reagan was a ''sponsor'' of ''state terrorism'' in Central America). But while he has worked hard at blandifying the rhetoric, he has afforded us no reason to believe that his substantive views have changed. His position on defense seems to be mainly that it's not really necessary. He opposes just about all the major new weapons systems, including several (Stealth, the Midgetman) that other Democratic candidates have generally supported. His foreign policy ideas still seem to be draped around a basically Marxist world view in which imperialist powers are endlessly preying on a mythically helpless Third World. Jackson's proposed solution to this problem seems to reside in his call for a ''new international economic order'' -- a proposal, always popular in the U.N. General Assembly, for massive North-South wealth transfers. When Jesse has attacked imperialists, he always seems to have American imperialists in mind. He definitely had them in mind when the Yankees went into Grenada, when they supported the Democratic Resistance in Nicaragua, and when they sent 55 (the limit imposed by Congress) military advisers to El Salvador. But when the subject is Afghanistan, Jesse has trouble seeing the invaders as imperialists or the victims as part of his mythic Third World. He apparently never let out a peep about the invasion. Wait, that's not quite right. We recently asked our old pal Nexis to point to all news stories in which ''Jesse Jackson'' occurs within 30 words of ''Afghanistan,'' and the exercise uncovered two peeps. In one of the stories, Jackson seemed to be arguing that the Soviet invasion of Afghanistan wasn't any worse than the American invasion of Grenada. In the other, he was developing the proposition that if the U.S. liked to go around supporting ''freedom fighters,'' such as those in Afghanistan, it should also be giving aid to the African National Congress in South Africa. The fact that the ANC is Communist-dominated possibly escaped him, but we doubt it. Folks yearning to view Jesse as a closet moderate will have trouble sustaining this agreeable thought when they get around to inspecting the characters he has selected as foreign policy advisers. Jackson's main one is Robert Borosage, who is on leave from the left-wing Institute for Policy Studies, of which he has been the director. Like most other IPS stalwarts, Borosage brings a Marxist orientation to foreign policy and was recently quoted as stating that a friendlier posture toward Cuba would help the U.S. ''to see the world in a more sensible way.'' Another veteran Jackson adviser, with the title of International Affairs Director for the National Rainbow Coalition, is Jack O'Dell, who was long ago identified in FBI records (released under the Freedom of Information Act) as an active Communist in the early Fifties. In 1956 and again in 1958, he took the Fifth when congressional committees asked about his party affiliations; later he denied any Communist ties. He also denies involvement with the World Peace Council, incontrovertibly a Communist front, but the council listed him as a member in the early Eighties. A few months ago, Tass, the Soviet news agency, quoted O'Dell as stating that Ronald Reagan's current commitment to an arms-control treaty was really ''a victory for the American people,'' who had supported scrapping of the missiles and left the Administration feeling it could not ''discard people's sentiments.'' This terrific analysis would possibly never have made it into this space but for the pressure to Take Jackson Seriously. We may not be able to sustain it.