Two Texans of uncommon skill were waging long-range warfare last week over the future of American domestic policy. The high-stakes game being played by James A. Baker III, the White House chief of staff, and Bill D. Moyers, the CBS News chief of commentary, revealed the marvelous subtlety of American politics, when the weapons of power are wielded by people of great dexterity.

In the same span of days that Baker was striving to salvage what was salvageable of President Reagan's fiscal policy, Moyers was laying down--in his hour-long documentary, "People Like Us,"--the most effective assault on that policy yet seen by the American people.

Moyers is a journalist and Baker is a government official. But both of them are politicians of the most serious sort, men consciously engaged in the struggle to shape the future of public policy. Moyers has gained a unique license from his employers to use the airwaves for that purpose. Baker enjoys unusual, if not unique, influence, because of his president's penchant for delegating authority.

Last week, Baker was playing the inside game, conducting negotiations with key congressmen of both parties on the reshaping of the federal budget. His chief weapon,. which he maneuvered with consummate skill, was the television witness of the president of the United States, doing his patented "nice guy" number as the seeker of compromise. But inside the negotiations, it was Baker striving for the concessions that would get Reagan off the hook of his own deficit.

Last week, Moyers was playing the outside game, producing, writing and narrating a television broadcast about the impact of that budget on four families. By reason of health, age, or economic adversity, they had become dependent on programs the government was reducing. His chief weapon was the unforced poignance of the stories he extracted from those unknown Americans--and the emotions his cameramen colleagues so vividly conveyed.

The tributes to the effectiveness of both men came from those on the other side. Noting that Baker had run roughshod in 1981 over the same Democratic leaders he was now trying to beguile into concessions, one top House Democrat said, "That so-and-so can beat you more ways than anyone I ever met."

And an administration operative, who watched Moyers' production, said, "As mad as I was at what he was doing, I couldn't help but feel the power of the message. He got us good." The White House demand for rebuttal time -- which CBS refused--was another indicator of the impact of Moyers' program.

Both men are pros in the power game, and both have consistently impressed their adversaries. Reagan wanted Baker because of the job Baker did working against him for Gerald Ford in 1976 and George Bush in 1980.

Moyers was a Lyndon Johnson prot,eg,e and operative, whose skills made John F. Kennedy eager to enlist him in his administration. He helped Sargent Shriver set up the Peace Corps, then moved back to Lyndon Johnson's side after the assassination, serving as press secretary and domestic policy adviser. Before Johnson fell from power, Moyers had left the White House to pursue his own career in publishing and then television. There are rumors that Baker may bail out on Reagan before this term is over.

Both of them attract the kind of envy and suspicion that goes with being very talented and very mobile. Some of LBJ's loyal staffers have never forgiven Moyers for leaving; Baker remains darkly suspect to true-blue Reaganites, who question his conservative faith and credentials. What John Connally used to say about Moyers' evil influence on Johnson is echoed in the warnings from Richard Viguerie about Baker's persuasiveness with Reagan.

Neither Moyers nor Baker has established a track record in elective politics, but at their ages--Baker is 51 and Moyers 47--they have time to try.

Baker made a losing bid for attorney general of Texas in 1978, and Moyers has looked at, but backed away from, races in both Texas and New York.

But no one who knows them doubts their ambitions are at least as great as their credentials. The respect they have gained will some day be converted to their own political use. For all their deliberately low-keyed personalities, their extraordinary politeness, their ready charm, there is no concealing the inner fires.

They have seen the presidency at close hand and have strongly influenced two of its strongest occupants. Both men, you can believe, wonder from time to time about how they would manage it themselves.

And from what they have shown this week, they might manage it very well.