Carry a big stick but speak softly - a lot more softly.
That, in effect, is the wisdom being urged upon America's official information agency, the International Communications Agency (ICA), by its national oversight commission.
Since last fall, ICA's new, more overtly political communicating style has drawn considerable public criticism.
In previous years the agency had taken pains to build its credibility in the world's eyes by reporting America's news and official positions in a low-key, ''objective'' style.
But under the Reagan administration, ICA has tried to explain America's more assertive geopolitical goals in more assertive ways. It has also tried to combat Soviet propaganda more vigorously. In the process, warned critics within the agency and without, ICA's information services were themselves starting to sound ''propagandistic,'' especially when it came to the agency's global radio, the Voice of America (VOA).
That concern has apparently gripped the ICA's independent, bipartisan oversight commission. In its new report released July 20, the presidentially appointed Advisory Commission on Public Diplomacy urges that VOA eliminate any stridency in its broadcasting that might jeopardize its credibility. It warns against private funding of government programs that articulate US foreign policy , such as ''Let Poland Be Poland,'' the Hollywood-produced, star-studded TV documentary that aired worldwide in February. While the commission supports ICA's new efforts to counter Soviet propaganda, it urges the agency to drop the name ''Project Truth.'' That name, it says, could increase suspicions of propaganda.
An ICA spokesman said the agency would give careful attention to these criticisms.
At the same time, the commission also thinks ICA should be allowed to wield a ''bigger stick,'' stressing that the country's communications and educational exchange activities are just as vital to national security as its diplomatic and military efforts. The commission wants the President and Congress to make ICA's director a statutory adviser to the National Security Council and the President.