In an effort to influence the foreign policy agenda, a group of neoconservatives is rolling out tonight what its members consider their ultimate weapon -- another magazine, pointedly named The National Interest and subsidized with a $600,000 grant from the right-wing Olin Foundation.

The neoconservatives are "neo" by virtue of being old liberals. Their numbers, including former ambassador to the United Nations and now National Interest board member Jeane J. Kirkpatrick, are few; their base is their brainpower, which has attracted the money. They believe that by their writings they helped prepare the groundwork for the Reagan victory. Yet, now, they believe that they need a new publication to help instruct a benighted administration at whose center is "a conspicuous void," in the words of the co-editor of The National Interest, Owen Harries.

In the quarterly journal's premier issue, the neoconservative elite is summoned by publisher Irving Kristol to lead a "war of ideology" to create what he calls a "new Republican Party." Kristol's credentials are considerable. He is the intellectual tutor to Rep. Jack Kemp (R-N.Y.), a potential presidential candidate in 1988. Moreover, Kristol has been indispensable in the creation of the supply-side economics movement through his influence with conservative foundations, editorship of The Public Interest magazine, and column-writing in The Wall Street Journal.

In Kristol's view, The National Interest can help produce a fervently ideological foreign policy to complement supply-side economic theory. "If there's going to be a new Republican Party," said Kristol in an interview, "then it will need a foreign policy to match . . . . The function of the magazine is to come up with principles and ideas."

Kristol's war of ideology would be simultaneously waged on several fronts. "The basic conflict of our times -- that between the U.S.S.R. and the United States -- is ideological," he writes. Our ideology, "liberal internationalism," early enunciated by Woodrow Wilson and based on notions of self-determination and international rule of law, is "naive and utopian," tragically inadequate in the world struggle.

In any case, according to Kristol, "liberal internationalism" is in decline, a "myth," shattered by the Vietnam War, which provoked three reactions. First, "liberal internationalism" regrouped as a self-loathing "isolationism," stressing human rights and "American subordination to international organizations" -- the Carter administration. Then, there has been a revival of "old-fashioned, nationalist isolationism" -- the dominant outlook of key parts of the Reagan administration such as Caspar W. Weinberger's Defense Department. And, finally, a "nationalist-unilateralist" tendency has appeared, disdainful of the North Atlantic Treaty Organization alliance with ungrateful Europeans, eager to go it alone. "This new conservatism," writes Kristol, "is self-consciously ideological," especially when it comes to "the basic conflict" with the Russians, which "we should aim to win . . . instead of pursuing a defensive policy that sees stalemate as the goal."

In the order of battle for this war of ideology, Kristol has assembled an impressive phalanx. On The National Interest's board sit not only prominent Republicans, former secretary of state Henry A. Kissinger and former Council of Economic Advisers chairman Martin Feldstein, but also prominent figures associated with the Democratic Party, including former National Security Council staff member Samuel P. Huntington and former Mondale speechwriter and New Republic senior editor Charles Krauthammer.

But the most eminent and accomplished Democrat on whom the neoconservatives counted to march in the front of their ranks is missing. In fact, Sen. Daniel Patrick Moynihan (D-N.Y.) can now be seen on the opposing ramparts.

In an Oct. 4 speech at the U.S. Military Academy at West Point, Moynihan said that "a myth of invincible communism" blinded U.S. policy-makers of the Vietnam War period to divisions and weaknesses within totalitarian ranks. These officials "lost sight of the options and sank into the continuous low-level warfare imagined in Orwell's 1984." The Cold War syndrome of recruiting "ideologists to fight ideologists," Moynihan said, had become a "vogue in Washington," most recently "for those whose early training was Marxist but anti-communist, or at least anti-Stalinist" -- an apt characterization of many prominent neoconservatives, including Kristol. This is a "new elite disposition" that tries to maintain, as in Orwell, " 'a continuous frenzy' over the threats we face in all corners of the world." Thus, Moynihan contended, we remain "mesmerized by the presumptive strength of totalitarian symbols."

Over decades, the neoconservatives have moved across the political spectrum from left to right. At every juncture they have been propelled by a feeling of disillusionment. Initially, they were disillusioned with the dream of Soviet Russia; then they were disillusioned with liberalism. "A neoconservative," said Kristol, in his famous formulation, "is a liberal mugged by reality." Now, the neoconservatives believe they have been mugged by President Reagan.

"There's been a disquieting gap between rhetoric and performance," said co-editor Owen Harries. "It's frustrating," said Olin Foundation director Michael Joyce. "Expectations were created by the rhetoric. When those expectations were unfulfilled you get a ferment."

As the neoconservatives see it, the Reagan foreign policy has been a succession of dismaying events. Though the president has excoriated the "evil empire," he ended the Polish sanctions, lifted the Russian grain embargo, disastrously withdrew from Lebanon, and did business with the Shiite hostage-takers. This incident incited Norman Podhoretz, the neoconservative editor of Commentary magazine, to accuse Reagan of "surrender . . . betrayal . . . loss of nerve . . . shame . . . caving in."

These episodes may be a prelude, in the neoconservatives' view, to the greatest betrayal of all -- a debilitating arms control agreement with the Soviets, the moral equivalent of appeasement. The possibility fills them with desperate urgency. "Virtually any politician whose career is in its last years," said Harries, "is going to be extraordinarily tempted to play it for history."

Despite Reagan's "general attitudes and instincts," according to Harries, he is held captive by the "old foreign policy establishment" -- extending from the Council on Foreign Relations and the Carnegie Endowment for International Peace, through Foreign Affairs and Foreign Policy magazines, to the State Department. This establishment, said Harries, is "still very powerful, entrenched, but has run out of ideas, doing it from memory." And the president "hasn't armed himself with people to provide him with countervailing advice . . . . None of the neoconservatives has been ideally placed." But from a magazine, Harries reasoned, perhaps they can "fill this conceptual void."

The National Interest had its origin in the Olin Foundation. "I was regularly hectoring Irving, not that he needed a lot of persuasion," said Joyce, the foundation's director. "The one thing foundations do is get the attention of people who are talented, because we have money to spend."

And he felt that the most efficient expenditure was on a journal, the essential mode of neoconservative politics. "To the extent that the neoconservative movement has any strength," said Joyce, "it's not in its numbers, but in sparking debate."

"Lenin," said Kristol, "understood that very clearly. What communists call theoretical organs always end up through a filtering process influencing a lot of people who don't even know they're influenced."

Kristol found the editor he needed for his new theoretical organ in Owen Harries, an Englishman turned Australian who was the foreign policy adviser to Conservative Prime Minister Malcolm Fraser. He came to the attention of the American neoconservatives as Australia's ambassador to UNESCO, which he denounced, supporting the U.S. withdrawal. Promptly, he became the first Olin Fellow at the Heritage Foundation. Harries considers the U.S. national interest as somehow supranational, the interest of the Free World in general. "America is the guarantor," he said in an interview. He argues that the "war of ideology" should be fought by the cunning statecraft of realpolitik.

Harries is joined as co-editor by Robert W. Tucker, professor at Johns Hopkins University, who calls himself "a genuine conservative." He fell into the neoconservative orbit when an article he wrote suggesting military seizure of the oil-rich Persian Gulf was rejected by Foreign Affairs. He offered the piece to Commentary, which published it in January 1975. Since then, Commentary has welcomed many other contributions from Tucker. Despite his position as National Interest co-editor, he is reluctant to join the war of ideology. "I don't deny the disparity between rhetoric and behavior," he remarked about Reagan's foreign policy. "I'm happy the reality doesn't live up to the rhetoric."

"I can't imagine that Bob Tucker will be very happy over the long haul with this company," said Richard Ullman, former editor of Foreign Policy and professor of international affairs at Princeton. "His view of the world is much more subtle and complicated than the views of, say, Irving Kristol and Norman Podhoretz. He will lend The National Interest more respectability than it would otherwise have. If the standards of intellectual rigor Tucker applies to his own writing are the standards he applies to the magazine, there are going to be a lot of disappointed would-be contributors."

Tucker, for his part, doesn't deny that there are "many differences within the conservative spectrum . . . . I'm sure we'll air them."

But The National Interest has been launched as an instrument in the war of ideology -- against the Russians, liberal internationalism and the old foreign policy establishment. "We've had ideological politics for quite a while now," said Kristol. "In the end, ideas rule the world because even interests are defined by ideas. The closer you get to the game of politics the less likely you are to see that."