This column was going to begin with a simple statement: Of all the "unknowns" hankering to be your next president, the one with the best chance may be Rep. Richard A. Gephardt (D-Mo.). But then I read a snippy column by Dave Barry in the Chicago Tribune and realized that I had to detour to my destination.

Barry wrote a piece recently promoting Julius Erving, the basketball star, as his candidate for president in 1988. He made a good case for Doctor J. The first time Mikhail Gorbachev shakes with the Doc and sees his teensy Commie paw disappear into Erving's wide-wingspread grip, the Cold War will be over. When Gorbachev sees him slam-dunk, he'll pull out of Cuba and Nicaragua and Afghanistan so fast it will make heads spin.

But Barry was unwilling to trust his own persuasiveness, so he trashed me and my ilk for publicizing people like Gephardt as presidential possibilities. "In fact," he said, "there is no 'Rep. Gephardt.' He was invented during a drunken gathering of the Established Political Pundits Assn. as part of an elaborate prank to see if they can cause a totally fictitious character to win the Iowa caucuses."

He is wrong on all counts. Established Political Pundits have vowed not to taste booze until the Chicago Cubs win the World Series. As for promoting "a totally fictitious character" as winner of the Iowa caucuses, that is no challenge. We already have done it twice -- with Jimmy Carter in 1976 and George Bush in 1980, neither of whom has been heard of since.

Whether Barry likes it or not, Gephardt is our man for 1988, and he is no fiction. I saw him at breakfast one morning last week, and he is right on schedule to be the "surprise" strongman of the 1988 caucuses.

Who is Gephardt? you ask. He is a 45-year-old St. Louis lawyer now in his tenth year in the House. He has red hair, boyish features and an engine that never stops running. He is chairman of the House Democratic Caucus and a member of the Ways and Means Committee.

That would be responsibility enough to keep most people occupied. Gephardt, however, is just a mite more ambitious. He is 30 years younger than Ronald Reagan. But he is two years older than John Kennedy was when he became president -- and getting older every day. That gnaws at him.

So he gets on national television news programs at every opportunity as a Democratic spokesman on tax reform, aid to contras or whatever. In 1985, a nonelection year, he campaigned in 30 states.

How did he do it? He says he was in Washington three or four days a week, depending on the House schedule. The other weekdays and three out of four weekends each month, he was on the road. He has an advantage in working Iowa, the site of the first 1988 delegate caucuses, because Ozark Airlines runs frequent flights from St. Louis to Des Moines. He can pop up there in 45 minutes, spend an afternoon or evening with some Iowa Democratic activists, and be back in his district before anyone knows he has been gone.

When columnist George F. Will asked him recently how a man with a wife and three children, ages 15, 12 and 8, could run for president in this marathon contest, Gephardt's quoted answer was, "I don't know." But when I asked a similar question, he said his family has agreed to his stepping up his already breakneck schedule. "I'm spending two days a week in the House, four days on the road and part or most of each Sunday with my family."

On the days he is in the House, he is systematically canvassing his Democratic colleagues for support of his presidential bid. He is getting pledges from many -- mainly in the South and the Border states, but also in the Midwest and on both coasts.

They like the idea of a House member's running for president. They like him. They know no one will outwork him. They think his moderate stands on most issues will make sense to the voters. They like being asked for their support. And they appreciate the point he makes to each of them that he will remember their help and solicit their views when he is president.

He is closer to putting together a national political organization -- through his House allies -- than his status as a political unknown would allow anyone to guess. If his constant cultivation of Iowa Democrats pays off in a win or a surprisingly good second place in the first contest of 1988, he will have a national network of credible political supporters ready to tell startled voters, "Of course I know him. I've been for him for a long time." If Gary Hart had had such allies in 1984, when he was the Iowa surprise, he would have been the Democratic nominee.

The morning I saw Gephardt, he had the flu. He should have been home in bed. Instead, he had a day of meetings and an evening fund-raiser ahead. He is going to be the tiredest 48-year- old in America if and when he reaches the White House.

He cannot rest and he cannot resist any challenge. When I saw him, I had not read Barry's column. Now that Gephardt is aware of it, I am sure there will be a basketball hoop in his backyard and 15 minutes of practice added to the daily schedule. If it's slam-dunks the nation wants, he will deliver.