Robert Caro's controversial biography of Lyndon Johnson, "The Path to Power," yesterday won the National Book Critics Circle award for nonfiction. Stanley Elkin's "George Mills" took the fiction award, "The Second American Revolution and Other Essays" by Gore Vidal won in the criticism category, and Katha Pollitt's "Antarctic Traveller" received the poetry prize.

The results of the eighth annual awards were announced yesterday by the NBCC Board of Directors after 5 1/2 hours of sometimes bitter debate at the Algonquin Hotel in New York City.

The principal acrimony centered on Caro's densely documented 882-page biography, the first of three planned volumes for Knopf, which follows LBJ from his birth in the Texas hill country to Congress to his unsuccessful bid for a Senate seat in 1941. Caro argues that Johnson's "hunger for power in its most naked form" was "so fierce and consuming that no consideration of morality or ethics . . . could stand before it."

The balloting split the 18 board members present between Caro's book and George Kennan's "The Nuclear Delusion: Soviet-American Relations in the Atomic Age" (Pantheon). One anti-Caro faction tried to defer consideration of the work until the trilogy was completed; others offered ad hominem remarks about Caro's credibility and alleged animus against LBJ. Caro partisans argued that since the Kennan collection includes little new work and even reprints interviews with the author, it was not suitable for an award for original writing.

Some directors felt that the Kennan backers appeared determined to make an anti-nuclear statement with their choice. When it became clear that support was waning for "Nuclear Delusion," the pro-Kennan group attempted to shift its support to Jonathan Schell's "The Fate of the Earth," which already had been eliminated in the early voting. But the strategy failed, and Caro finally won by 11-4, with three abstentions.

A more genteel argument ensued over the fiction prize, which rapidly devolved into a contest between Elkin's novel and Cynthia Ozick's "Levitation" (Knopf), a collection of four stories and a novella--although Anne Tyler's "Dinner at the Homesick Restaurant" (Knopf) had strong support. In the end, the board chose Elkin's book for its vast sweep, exuberant prose and sheer ambition. It follows the impecunious but doggedly pragmatic Mills clan (which produces one son per generation, each named George) from the Crusades to the present in a grimly comic panorama of social satire.

Gore Vidal's strong showing on the first ballot surprised a number of board members who feared he might be too controversial to win. But the lustrous prose and elegant acerbity of his collected essays from 1976 to 1982 (Random House) won him the prize, despite early support for Arlene Croce's "Going to the Dance" (Knopf), Marshall Berman's "All That Is Solid Melts into Air" (Simon & Schuster) and "Agon" by venerable literary critic Harold Bloom.

The poetry voting pitted two Knopf authors against one another: Katha Pollitt, literary editor of The Nation, and Brad Leithauser, whose meticulously formal anthology, "Hundreds of Fireflies," had the second-largest following. But Pollitt's rich synesthesia ("Like a dark foghorn in the yellow kitchen/ we imagine the eggplant's/ melancholy bass/ booming its pompous operatic sorrows . . . ") eventually took the prize.

The NBCC board is also empowered to grant a special prize for general literary distinction: The Ivan Sandrof-Board award, named after the NBCC's founder and first president. It has only been given once before, to Flannery O'Connor. Yesterday the directors unanimously voted to honor scholar Leslie Marchand for his lifelong work on the poetry, letters and journals of Byron.

The NBCC, founded in 1974, began its award program in 1975 for books written in English by American authors. The five nominees in each of four categories are determined by a two-part process: Ballots received from the general membership of 300 professional book critics and editors determine up to three books in each category; the remainder are chosen by the NBCC's 24-member board of directors. The latter provision was the cause of some embarrassment yesterday, when two books nominated by directors only--Bobbie Ann Mason's story collection "Shiloh and Other Stories" (Harper & Row) and poet W.S. Merwin's "Finding the Islands" (North Point Press)--failed to get a single vote, suggesting to some board members that their nominators had not actually read them.

This year four board members are from Washington, the second-largest city representation after New York: Jack Beatty, literary editor of The New Republic; Bruce Cook, book editor of USA Today; Timothy Foote from Smithsonian magazine, and Brigitte Weeks, editor of The Washington Post Book World. And Vanity Fair magazine, which the Conde' Nast group will resurrect in March, has emerged as a power in the NBCC, with four directors on its staff: editor Richard Locke (NBCC president); Walter Clemons (formerly of Newsweek); John Leonard (formerly of The New York Times), and Elizabeth Pochoda (formerly of The Nation).

The awards--which do not include a cash prize--will be presented at ceremonies at the Time-Life Auditorium in New York Thursday, Jan. 27.