From left to center; Jockeying for thinkers, funds, and influence, Brookings puts scholarship over partisanship

''My job,'' says Roger Semerad, ''is to modernize the way (Brookings) does its business.'' As executive vice-president of the Brookings Institution, Mr. Semerad occupies a corner office at the home of the nation's oldest public-policy research organization. To visitors aware of Brookings's reputation as a think tank aligned with Democratic Party positions, his office is full of surprises: In addition to the large American flag, the decorations include a photo of an elephant, a bronze eagle, and a bust of Lincoln.

Mr. Semerad, in fact, is a self-described ''small C, capital R'' conservative Republican - a White House staffer under Presidents Nixon and Ford, who served as executive director of the 1980 Republican Platform Committee.

So his word ''modernize'' has several connotations. While he remains proud of Brookings's past successes - in helping develop such ideas as unified budgeting for the federal government, the establishment of the Congressional Budget Office , and revenue sharing - he is now laboring to bring Brookings up to date in its fund-raising activities. He hopes, too, to make the institution more visible to the public.

Semerad is also working to ''modernize'' the image of Brookings. He came to the institute in 1981, he says, to help lift it out of what he describes as ''tinker time'' - the period in the nation's history when the government's role was seen to be to ''tinker with the economy, tinker with our lives.'' He describes his mission as one of ''reality therapy'' - moving the institution away from the left and toward the nonpartisan center.

In his office nearby, Brookings president Bruce K. MacLaury - a former deputy undersecretary of the Treasury under President Nixon - admits that he himself was appointed in 1977 because, as the then-president of the Minneapolis Federal Reserve Bank, he came from a ''nonpartisan'' institution. The 1960s and '70s, he says, left Brookings with the ''perception of being on one side of the political fence.'' He has worked to return the organization to its original mandate of doing ''scientific research'' on public-policy issues - which he defines, not as ''position papers'' reflecting a certain ideology, but as ''reasoned analysis.''

Brookings, clearly, is moving right. The change, a gradual one, has arisen partly as a pull and partly as a push. The pull has come from a desire to shed the ideological labels that could interfere with its goal of producing unbiased research. The push, however, has come from the severe competition Brookings faces in the marketplace of ideas - much of it from the right. Taken together, these forces place Brookings, notes Semerad, at ''a very critical juncture'' in its history, facing several challenges:

* In an arena that for years it occupied almost alone, Brookings now faces scores of new think tanks, many of conservative stripe, which have been set up in recent years. The result: increased competition for funds, for people, and for influence.

* While Brookings continues to produce its 30 to 35 publications a year (most of them book length), it must also respond to the need for shorter, more timely reports of the sort produced by two of its right-leaning Washington neighbors - the American Enterprise Institute (AEI) and the Heritage Foundation.

* Yet it must resist moving too far right - or too far toward quick, compact work. Its reputation, after all, still rests on the comprehensive research done by its well-established core of economists, which includes such luminaries as Alice M. Rivlin, Charles L. Schultze, Joseph A. Pechman, Barry P. Bosworth, and Henry J. Aaron.

''My job is not to turn this into a conservative think tank,'' says Semerad. On policy matters, he adds, there is never ''any one answer,'' but a collection of ''clear choices.'' Helping provide such choices these days within Brookings are such conservatives as Thomas O. Enders (a former assistant secretary of state under President Reagan) and Malcolm R. Lovell, a former undersecretary of labor under Mr. Reagan; Mr. Lovell is a guest scholar.

As though to prove the value of such choices, Brookings and the AEI are cooperating on several projects, including a January briefing session for freshman congressmen organized by the Congressional Research Service. On matters of ideology, says Semerad, ''AEI and Brookings really have been pushed into the middle.''

For Brookings, one result of that move toward the center has been an increased ability to attract funding from the typically conservative private sector. The institution has already secured some $1.7 million in donations from nearly 200 corporations, says Dr. MacLaury.

In the competition for influence, too, Brookings has taken some major steps. It still retains its three research programs (in economic, foreign-policy, and governmental studies), and still addresses a wide range of subjects. Its Advanced Study Program still produces conferences, which last year drew some 2, 600 attendees. But it has added a full-time public affairs office to work more closely with the press. Two years ago, it began publishing the The Brookings Review, a quarterly journal, as a forum for shorter and more immediate comment. And the staff is now working to shorten the lead time needed for publishing its books.

Where does Brookings go from here? With a staff of about 50 scholars, MacLaury says that his institution is ''really not deep in very many areas.'' He plans to add specialists on Latin America, agricultural policy, and developmental economics. The reason: Brookings, like most think tanks, likes to foresee problem areas.

''We try to be ahead of the curve,'' says Semerad, adding that at Brookings the ''only job is to go beyond the surface to find out what might happen or what has happened. If there are lessons in history,'' he concludes, ''then our work is vital.''

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