Margaret "Midge" Costanza, President Carter's public liaison chief, last night showed a Kirkland House audience how she has earned her reputation as one of the administration's most outspoken and controversial figures.

Covering a broad range of issues--from human rights to abortion to union-busting--Costanza told the crowd of about 100 that "the major problems in this nation are those which deny citizens their human dignity."

Costanza deseribed her efforts to convey the feelings of the American people to Carter since he took office.

More than PR

"It's not just Public Relations." She said, adding that in recent months her job has come to include writing letters to fellow administration members in an effort to persuade them to change their positions on key issues.

Costanza said the initiatives have been entirely her own, and added that the results have been encouraging.

Costanza, whose open clash with Carter last year over his stand against the use of Medicaid funds to finance abortions brought her extensive media coverage, speculated that if she had expressed similar disagreement in the Nixon administration. "I would have been aborted."

On one occasion, Costanza lapsed briefly into a humorous, drawling imitation of her boss. "Not only am I liberal and progressive, but I could also be considered weird," she said later.