At 8:30 this golden Sunday morning, back by the Delta Airlines airport gate, an unhappy-looking reporter fiercely chomped on his cigar and scratched out these words in his notebook: "George Bush: The intention of the convention. . . . "

That was as far as he got. He stared gloomily ahead as the minutes passed, but the words wouldn't come. Try as he obviously did, he couldn't find something to say to justify his being there so early in the morning.

George Bush didn't have much better luck. His plane was late, and he quickly dispensed with the ritual airport news conference staged before a small group of reporters. Then, while the TV cameras continued to roll and the lightbulbs flashed, he began strolling through the airport crowds to a waiting limousine.

"Do you know who that is, Sarah?" a man said to the woman beside him. She stared at the scene and the tall slim figure in the center, shook her head and said, "No."

So much for yesterday's hero. Politics is cruel, and at national conventions the erstwhile front-runners (for a time) become the forgotten also-rans (unless, as might be the case with Bush, they end up on the ticket). a

And so much for this convention city, where the frivolous and the foolish drive out the attempts at seriousness.

Two hours later another also-ran, Sen. Bob Dole of Kansas, was trying to get his fellow Republicans to focus on the way they pick their presidential nominees. He was urging the Gop's Rules Committee to establish a shorter, more orderly system. The present long, costly drawn-out primary system, he said, is leaving many voters feeling disenfranchised and is forcing the candidates to "focus too much on the superficial and the trivial."

A Republican judge from New York had similar words of warning -- "the political system is being undermined" -- and the liberal GOP Ripon Society was offering a stinging policy paper calling on the party to change aspects of its structure that have "indirectly but systematically discriminated" against Jews, blacks, Hispanics, Catholics and Southern Baptists.

But on this sparkling day at least the Republicans were having none of it. They were glorying their present, rather than pondering some problems in their future.

They were, for all to see, acting the way delegates always act -- milling around in the hotel lobbies, gawking at the occasional celebrities, buying this convention's silly button or bumper sticker ("Unemployed: Made in Japan," was one with more bite than usual) watching as journalists interviewed journalists everywhere they met, and helping redress Detroit's devastated economy by filling the bars and restaurants and spending as if they had never heard of inflation.

As each of them knows, they are bit players on a large stage -- for the moment, the grandest in the world -- and they appear eager to enact their parts. Whatever suspicions and doubts these delegates may harbor toward the national press, their nemesis of conventions past, are suppressed in their obvious desire for national publicity for their party and their new leader, Ronald Reagan.

At a church service this morning attended largely by convention delegates and a GOP senator or two, those present watched patiently as the press crowded around the pulpit and TV technicians strung lines along the aisles.

The service, not without political overtones, took note of the American hostages in Iran. When the minister invoked not only scripture but quoted from "General and President Dwight D. Eisenhower" and warned darkly of America being overrun by foreign enemies unless it is properly armed, the GOP faithful in the congregation listed with proper attentiveness and approval -- and all the while the scene was being captured by the TV cameras.

Even more than other political gatherings, this convention is dominated by television. Detroit today is a city spun with electronic cables and awash in TV personnel, who far outnumber delegates.

Watching this scene unfold before the reallife action begins gives a feeling of seeing the actor playing himself. Over at Joe Louis Arena, a biscuit box of a convention center sitting alongside the Detroit River, the stage awaits the players, but in many respects the principal actors are already there: the TV floor reporters and their camera crews busily rehearse their possible scenes throughout the hall and respond to directions from the network anchor booths and control rooms.

Posters of Reagan adorn the hall, along with the new slogan, "Together . . . A New Beginning."

Witnessing this now-dark stage in its final hours of rehearsal makes you think you are present at a Potmekin Village where the set becomes reality, and all behind it is empty.

The Republicans could not have chosen a more symbolic city of reality for their convention, however. Detroit ranges of extreme wealth and poverty, its neighborhoods of Tudor mansions along the water and grim streets of dilapidated housing and crime, are on display for all who want to see.

Out Jefferson Avenue on Saturday afternoon the scene at two places not far apart told part of that story. In Grosse Pointe, just over the city line, the private park surrounded by a tall wrought-iron fence was filled with picnickers enjoying the summer in their sporting goods store clothing. They were all white.

A few blocks away, across the bridge to Belle Isle, the public park was filled, too, but with virtually all blacks. The garbage cans there were overflowing from the just-ended municipal workers strike.

And on Helen Street, when you came back from the island, a group of blacks were sitting on the corner of a street "NEIGHBORHOOD WATCH" -- a crime warning by the Detroit Police Department.

They weren't much impressed by the GOP doings downtown.

"There's too much happening here now," said Mary Alice Ward, "people being mugged in broad daylight and no jobs." She pointed to a Uniroyal factory across Jefferson Avenue. The plant shut down recently, throwing thousands out of work, one of the latest casualties in Detroit's failing economy.

She and her neighbors are not without civic pride, but, as they said, they didn't see how the Republican convention would help them. "They're not for the minorities and ethnics," Ward said. "They're bringing in lots of money now, but who's it going for?"

But they weren't entranced bt the Democratic president either. "Carter, he's a good man, but he's too 'leaning,'" said Robert Woodward, 56, who works at a steel plant nearby. "I mean, he's got a soft heart, but he lets the communists push him around."

In that, at least, the Republicans downtown could take heart. They could do worse than recruit Woodward for their spectacle that's about to begin. He's the symbol they need -- the missing black, surrounded by poverty, who thinks it's time to get tough.