Send in the tanks.

WHEN Ed Feulner was a Capitol Hill staffer in the early 1970s, he recalls, conservatives in Washington could hold their meetings in a phone booth. The problem wasn't just numbers, but influence. Liberals dominated the news media, academia, trade unions, interest groups, book publishers. Indeed, they still do. But over the past two decades, another institution has carved out a crucial role in the national debate. And this institution, the modern public-policy think tank, is largely the creation and domain of conservatives.

"I think that over the past twenty years, think tanks have had a significant impact by adding new ideas to the political dialogue," says David Boaz, executive vice president of the Cato Institute. Such issues as transportation deregulation in the 1970s, privatization in the 1980s, and medical savings accounts in the 1990s are all examples of causes that other institutions -- such as business groups -- could have championed in Washington, but did not.

Similarly, the traditional sources of independent public-policy research and analysis were universities. But as Martin Anderson, domestic-policy advisor to President Reagan and currently a fellow at the Hoover Institution in California, explains, academic researchers have lost their ability to produce anything serious and relevant. Instead, they turn out work that is esoteric, often erroneous, and largely unreadable. "Nobody reads even prestigious academic journals any more," he says. But policymakers do read the work of think tanks.

The reason is that think tanks, unlike universities, have a clear understanding of who their customers are. Take the Heritage Foundation. Founded in 1973, it is the largest of the Washington-based conservative think tanks, with a 1994 budget of $25 million. Its Capitol Hill headquarters have become a familiar landmark for lawmakers, Administration officials, reporters, lobbyists, and activists.

Heritage has teams of researchers working on almost every conceivable topic of public interest. But as Ed Feulner, its president, explains: "We view production -- that is, conducting research, analyzing the data, and publishing the findings -- as only part of the total process. The other key part is marketing --the way in which we package our findings, our distribution network, and the various activities aimed at building support for our ideas."

Heritage came into its own in 1981, with the election of Ronald Reagan and the simultaneous release of Mandate for Leadership, which laid out an agenda for the Reagan Revolution. Since then, Heritage has had a significant impact across a range of issues. Its election-year briefing book, Issues '94, was popular among congressional candidates. Its magazine, Policy Review, has helped set the agenda in the nation's capital. And its Town Hall service on CompuServe and the Internet gives thousands of conservatives across the country and around the world a forum for debating and exchanging ideas.

The Center for Strategic and International Studies is a longtime fixture on the foreign- and defense-policy scene, operating research programs in such areas as international politics, military affairs, science and technology, and international business. Its 1994 budget was $15 million, and its board of directors has included some of America's most distinguished statesmen, such as former Secretaries of State Henry Kissinger and James Baker, former National Security Advisor Zbigniew Brzezinski, and former Federal Reserve Board Chairman Paul Volcker.

CSIS, under the direction of David Abshire, was founded in 1962 as a program of Georgetown University, and became an independent organization in 1987. Among other activities, it provides testimony and expertise to congressional committees and Administration officials; operates international "action programs" with CSIS scholars, business leaders, and government officials in such countries as Russia, Poland, and Argentina; and publishes a journal called Washington Quarterly.

The venerable American Enterprise Institute, founded in 1943 and now headed by Christopher DeMuth, is the third-largest tank with a 1994 budget of $13 million. Its role in the market for conservative ideas has historically been a scholarly one -- publishing a steady stream of books and monographs on public policy and providing some of America's leading conservative thinkers with an inside-the-Beltway roost. Jeane Kirkpatrick, Robert Bork, Charles Murray, Michael Novak, Ben Wattenberg, and Dinesh D'Souza are just some of the authors AEI has housed in recent years.

While the Heritage Foundation receives a significant portion of its revenues from individuals and foundations, AEI is the most popular think tank among large corporate givers. In 1994, according to the Capital Research Center, major corporations gave AEI almost a million and a half dollars, versus less than half a million for Heritage. One reason may well be AEI's longtime focus on economic and regulatory issues, ranging from fiscal policy to the operation of federal administrative and regulatory agencies. AEI publishes a bimonthly magazine on politics and public policy, The American Enterprise, now edited by Karl Zinsmeister.

The libertarian Cato Institute's roots are outside the Beltway --in San Francisco, where it was founded by president Ed Crane in 1977 as a quasi-academic organization, holding events and publishing an academic journal. After its 1981 move to Washington, however, Cato began to focus more directly on public policy. Its studies tend to be lengthier than the average Heritage Backgrounder, and often more philosophical. But on some issues, such as state and local fiscal policy and deregulation, Cato frequently turns out the best and most detailed work available.

Some indication that the times have changed in Washington can be found in the fact that in 1995, Cato (whose 1994 budget was $6 million) hired its first director of government relations. David Boaz told me that in 1993 and 1994, Cato policy analysts testified a total of six times before congressional committees. In January 1995 alone, Cato scholars headed up to Capitol Hill for committee testimony more than thirty times. And a recent conference on Social Security privatization -- a longtime Cato cause -- drew 35 members of Congress.

The Specialty Shops. Heritage, CSIS, AEI, and Cato are only the largest of the Washington think tanks. There are also specialty shops which can be found in virtually every area of public policy. Here is a sampling of some of the best-known and most influential:

The American Legislative Exchange Council is an association of state legislators that advances a conservative, free-enterprise agenda. The Capital Research Center is the conservative watchdog of the philanthropic and nonprofit sectors. The Center for Security Policy addresses emerging issues of national security and foreign policy. The Competitive Enterprise Institute works primarily on issues related to the environment, finance, energy, and health care. The Free Congress Foundation is best known for founding a conservative cable network, National Empowerment Television (NET). The Media Research Center is the largest of the conservative media-watchdog organizations. The National Center for Policy Analysis was one of the originators of the medical savings account. The Tax Foundation does work on federal, state, and local taxation and computes Tax Freedom Day each year. The Washington Legal Foundation litigates cases on such issues as property rights, food and drug administration, and civil rights.

These and dozens of other organizations provide the conservative movement with a solid infrastructure for challenging liberal institutions. In Washington, the days of the conservative phone booth are over.