The policeman leaning up against the telephone pole at 22nd at G pointed down the street and said the closest place to sit and have coffee was the Roy Rogers on Pennsylvania. So 18-year-old Alex Yazza, who had come all the way from Windowrock, Ariz., to participate in the National Indian Youth Leadership Conference, funded by the Department of Labor, ended up sipping a Coke in the King of the Cowboys' version of McDonalds, where the walls are plastered with lassos and branding irons and six-shooters, and the teen-agers behind the plastic counter serve holsters of french fries.

Yazza, asked what he thought of Roy Rogers' cowboy and Indian movies, smiled to himself.

"I watched a few of them on Sunday afternoon TV. One thing I noticed about those movies is that the Indians are always getting beat. I wonder, were we that bad?"

"I was born and grew up in Fort Defiance," he said, "which was the headquarters for Kit Carson, who rounded up the Navajos for the Long Walk to Fort Sumner."

He took a deep breath, leaned over the table and raised his voice slightly. The Kit Carson story had reminded him of another point he wanted to make.

"They sent us back to where we came from thinking it was a bad piece of land. Now we've discovered everthing there - coal, oil, uranium. That makes me feel good. Thought they'd put us out there in the middle of nowhere..."

Of medium height and fine black hair, wearing tinted glasses, Yazza believes that his tribe, the Navajos, have been vindicated by recent history.

He has no qualms about being a part of "the American way," as he calls it. He wants to go to college and major in political science; he celebrates Thanksgiving, Christmas and Easter; he discos; he dates; he was president of the student council.

Last year, while he was president, the student council started what he called the disco system.

"In past years, we hired bands for $300 a night. This year we formed our own disco. I was the DJ. We bought our own strobe light and crystal ball, our own turntables, amps and speakers, our own records and mikes. We had dances every Thursday night in the gym, and practically the whole school turned out for them."

Tuesday morning, he led a sleepy discussion session for group 13. (He was elected its president on Tuesday.) A psychologist speaking to the 300 students at the conference asked them to split into small groups and resolve one of these three problems in five minutes: courtship restriction and teen-age pregnancy, adoption, or self-image and the family. (Earlier the psychologist had asked everyone to draw an aardvark. He predicted that all the drawings would be different. "You all see the world in a different way even though you're all Indians" he said.) Yazza's group filed outside and sat silently in a row on the cement bench. Yazza stood before them and made a brave attempt to lead a discussion.

Monday morning, the conference-goers, mostly high school students, visited the White House, where the president made a surprise appearance.

"We went to the South Lawn and had punch and cake. Then out of nowhere the president came walking up. That was quite a surprise. I was in a daze. My supervisor took a picture of me shaking hands with him. How many times would you get a chance to meet a president of this great nation?

"I would like to see an Indian up there someday," he added.

"Do you want to be president?" he was asked.

"I'll become what I become. I can't say what I'm going to do until I do it," he said cagily.

Yazza got interested in politics and in helping his tribe when he went to the Bureau of Indian Affairs high school in Windowrock.

"I had friends in junior high who were into athletics. But as soon as they went to high school they got into drugs and alcohol. There was nothing to do at home, so I ran around with them for a while. They would jump in a truck, go to the nearest town, buy booze, streak like crazy up into the hills and get bombed. I was the oddball because I never wanted to go," he said.

"Over half the Navajos are under 17," he said, "and there is a very high drop-out rate. I always ask myself, "Why?". I don't say anything that would cut them low; I almost dropped out myself. But I didn't because I got into other things," he said.

"Sophomore year I sat in my house one afternoon - alone - I sat there and thought about what is going to happen in the next 15 or 20 years. We can't depend on the tribal council to solve the problems of youth. The older folks don't always understand the younger ones. Youth wants to be heard and wants things on the reservation - more recreation and employment. The older ones never had such things and can't understand that times have changed.

"It's today," he said, shaking his head. He seemed frustrated that some people just don't understand that. CAPTION: Picture, Alex Yazza; by Joe Heiberger