Can a ''dark horse'' make it out of relative political anonymity all the way to the White House?
Jimmy Carter did it. But establishment Democrats say that outsider Carter, because of a record they deplore, gave dark horses a bad name - and that the party now will be especially reluctant to hand its nomination to an unknown.
That's the struggle in which Reubin O'Donovan Askew, from 1971 to 1978 a highly regarded Florida governor, now is involved.
First, as he knows, he must establish his credibility as a presidential candidate, as someone the national press will take seriously. In this vein he had to explain his answer to reporters assembled here in 1972 when they were pressing him about his aspirations: ''I don't want to be President,'' he had said then.
Then in 1976 he had taken a similar position in talking to this group. Now, as he looks back, the man who could be described as somewhat resembling a younger Ronald Reagan says he realizes that he simply had felt at that time he was not sufficiently prepared to be president.
Today, he says, with the governorship and experience as Mr. Carter's US trade representative under his belt, he believes he is ready to provide presidential leadership.
So, without any badgering this time from the media about whether he was interested in running for president, he is taking the initiative himself. He's, indeed, running hard.
Already, says Askew, he has probably done more traveling than any of the other more visible possible Democratic candidates, including Sen. Edward M. Kennedy of Massachusetts and former Vice-President Walter F. Mondale, in his quest of the presidency. ''I've been in every state in the United States at least once since January,'' Askew says, ''to make political appearances.''
''One thing I wanted to find out was whether I had the stamina for the long campaign,'' he says. ''I've found out that I do.'' Here he hints that perhaps some of the other candidates didn't have the strength and determination to stay the course.
''Another thing I've found out,'' says Askew. ''People out there want someone other than Mondale and Kennedy.'' He says the many Democrats he's talking to don't want the party ''to take a turn to the left.''
Askew says he sees himself as a ''centrist.'' He favors government spending for jobs at this time, simply to provide hope for the unemployed. But he would like to see only a ''modest'' outlay because he doesn't view it as a long-range answer.
The central theme of Askew's emerging candidacy is still a little sketchy. But he is asserting that the country needs a president who comes in with a new agency for revitilizing the economy, one that will be based on making the United States competitive with the rest of the world.
He talks about a new labor-management relationship that would be more cooperative than competitive - one he says is necessary if a lasting upsurge in the US economy is to come.
How would he separate his approach to shoring up the private sector from that , say, of a Gerald Ford? Askew obviously is more liberal. He says the government should play an important spending role in revitalizing US business. Otherwise, he says, the US will have to travel the high tariff, protectionist route that he feels would be most undesirable.
At one point he describes ''the whole economic infrastructure in the country'' as ''needing attention.'' ''We need a new attitude of labor and business,'' he says, ''one that is far less adversarial.''
Askew sees himself as being prepared, as president, to become the ''catalyst'' in pushing through his new agenda that would revitalize the US economy. Askew faults Reagan's big tax cut, says he should have made ''a major adjustment earlier on'' when ''he should have known that it wasn't bringing about the stimulation to investments that he had forecast.''
Askew wants a strong defense. But he says the first task is to move the US economy forward -- and then, from the increased revenue that would result, would be found ample money to beef up the military.