Two activist Roman Catholic nuns in Rhode Island are challenging, each in her own way, the determination of Pope John Paul II to get priests and nuns out of the political arena.

Last week, Sister Arlene Violet, 40, a lawyer who is active in public interst causes, resigned from her religious order, the Sisters of Mercy, when her bishop denied her permission to run for attorney general of Rhode Island and remain a nun.

Church law says that a priest or member of a religious order may not "assume public office which involves the exercise of civil power" without permission from both his or her immediate superior and from the bishop of the area involved.

Nearly four years ago, Pope John Paul dramatized his dislike of clergy in public office by forcing former Massachusetts representative Robert Drinan, a Jesuit priest, to drop out of partisan politics.

Violet ran for the post two years ago and lost to the Democratic incumbent.

Providence Bishop Louis E. Gelineau issued a statement disapproving of her candidacy, but she maintained that canon law at that time did not bar her from running.

But the new code of church law that went into effect late last year specified the need for Gelineau's permission, which he refused on Jan. 5, saying "I must agree with the pope who considers the candidacy of priests and religious for political or public offices contrary to what the church expects of those chosen by Christ and dedicated to the church."

So Violet renounced her religious vows of 23 years in order, she said, to "make the law work to improve the quality of our individual lives."

A second Rhode Island nun, Sister Elizabeth Morancy, 42, also a Sister of Mercy, is completing her third term in the Rhode Island House of Representatives and has said she intends to run again.

A widely respected social worker, she has said she will neither resign from the religious order nor request permission from the bishop to seek a fourth term.

If Morancy pursues her course of ecclesiastical civil disobedience, the Vatican can order either Gelineau or her religious superior, Sister Noel Blute, to discipline her. Blute could not be reached for comment.

Last spring a Michigan nun, Agnes Mansour, was forced by the Vatican to choose between her post as state director of social services and membership in her order, the Sisters of Mercy of the Union.

The Vatican's action in the Mansour case was bitterly protested by organizations of men's and women's religious orders.

Now, the reemergence of the issue in Rhode Island is expected to escalate tensions between the church's conservative pontiff and the progressive women's religious orders in this country, which are already under Vatican pressure to mend their liberal ways.