Colleen Dewhurst in an assertise portrayal seems so ideal a political candidate that one tends to endure "An Almost Perfect Person" despite its obvious imperfections.

It will, perhaps, be interesting to see what happens to this political comedy that opened two weeks ago at the Belasco. Author Judith Ross has worked the political field from California to Manhattan, co-producer Burry Fredrick now is New York's leading female producer, and actress Zoe Caldwell here makes her bow as a director. A ghostly background figure is Bella Abzg, who like the Dewwhurst characters almost perfect person, lost a mighty political battle. Women's patronage is patently sought. Will it appear?

In the play, Irene Porter, a Democrate, has just finished a rugged campaign for the House of Representatives, and at 3 o'clock on Wednesday morning, she appears to have lost. A widow with two children (invisible), she has had no visitors to her bedroom since her husband's death. Her campaign manager declares taht if she had embarked on the TV campaign he had planned, she might have won - but there is some comfort in going to bed. Her CPA, an inhibited fellow who is not happy with his wife, reveals that the campaign, without TV, put her $75,000 in debt - but there is some comfort in going to bed.

In other words, Irene Porter, is in the same position as a man whose security has been rocked be failure but who is psyclogically strengthened by two sexual conquests within a few hours. Because the political outline sketched by author Ross suggests that the candidate is both politically and fiscally impractical, I assume she intends the sexual conquests to be the more important aspect of her comedy.

I cannot fault this joke on the double standard. If men can get away with two-timing, surely women have the right.

But the unrealistic idea that any candidate can expect to win a contemporary election without the benefit of TV commercials does seem vacuous; and why on earth doesn't Porter realize where her campaign funds are going?Opting for consistency on the sexual level, Ross ignores consistency on the political one.

Still, Dewhurst is so strong and, here, genial an actress that one follows Porter's adventures with sympathy. The two men's roles are not so deep t the campaign manager, George Hearn is excellent as an individual of whom Porter just might approve. As the more stereotyped accountant, Rex Robbins suggests that dealing with money has left his Jerry Leeds hungry for romance.

Women in politics is not new to the stage but Ross has exploited the current atmosphere awarely. In Fay Kanin's "Goodbye, My Fancy," Madeleine Carroll was a congresswoman in the bonds of stricter sexual customs, but the play had the advantage of subplots and nearly a score of subsidiary characters. With only three characters in "An Almost Perfect Person," Ross has a tougher challenge.

The Caldwell direction is exemplary in that it serves the play astutely. Too bad the play isn't richer and firmer.