Ever since the Center for Strategic and International Studies (CSIS) forced its new president to choose between thinking and politicking, senior administrators all over tank town have been reminding their scholars about the do's and don'ts of advising political candidates.

A survey of think tank administrators found that policies vary, but only slightly. "Our policy is the same as the others," said Cheryl Rubin, director of public relations at the Heritage Foundation. Partisan politicking by scholars "must be done on their own time, and not under the official auspices of our organization."

She said when Heritage President Edwin J. Feulner Jr. signed up three years ago to become GOP vice presidential nominee Jack Kemp's "right-hand man--pun intended--he took a leave of absence."

Likewise at the Center for National Policy. "Should any CNP staff person wish to work on a campaign, he or she must take a leave of absence," said spokesman Justin Leach. That's exactly what Secretary of State Madeleine K. Albright did in 1992, Leach noted, when she stepped down as CNP president to work on Bill Clinton's campaign.

"We really discourage the idea that people become part of a brain trust or become really closely affiliated with a given candidacy," said Ed Crane, Cato Institute president. "I think that's a mistake for a think tank." Instead, Cato encourages its thinkers to "provide advice to any candidate who wants it."

Such open-door policies are common because they keep the IRS at bay. The tax code expressly prohibits nonprofits such as think tanks and foundations from participating in political campaigns. As much as tanks relish power and cachet, they value their 501(c)(3) tax-exempt status even more--witness the decision last month by the CSIS to part ways with Robert Zoellick after four months on the job because he serves as an adviser to Republican Texas Gov. George W. Bush's budding presidential campaign.

At the Brookings Institution and the American Enterprise Institute, scholars are warned not to work on partisan campaigns while they're on the job. However, "occasional kibitzing with a candidate or campaign staff" is okay, wrote AEI President Christopher DeMuth in a recent memo.

NEW AT ASPEN: Chicago superlawyer and onetime General Motors executive Elmer Johnson is the new president of the Aspen Institute.

"I am delighted to have the opportunity to be more closely engaged with this extraordinary organization," Johnson said.

No doubt. The institute is based in Washington, but it's best known for the lavish conferences it organizes in Aspen, Colo., and equally swank locales in France, Germany, Italy and Japan. When not distracted by the swank, these assembled leaders of business, labor, government, the professions and the arts discuss "timeless ideas and values," according to an institute release.

Johnson, 67, a partner at the law firm of Kirkland & Ellis, has been a member of the Aspen board of directors for more than 10 years. He takes over from Charles Knapp, a former president of the University of Georgia who served two years but apparently had second thoughts about leaving the groves of academe for the groves of Aspen.

"As he told us, his passion is in higher education," said Linda Lentz, the institute's vice president for communication.

Knapp may be leaving the Aspen Institute, but he's not going far. He has joined Tulane University's Payson Center for International Development and Technology Transfer at its D.C. offices.

VACATION IDEA: Thinking about thinking this summer? The Cato Institute has the perfect vacation getaway: the Cato University Summer Seminar, to be held the first week in August at the ultra-posh Rancho Bernardo Inn near San Diego. Institute scholars and academics will lead seminars "exploring the ideas of liberty." The only entrance requirements are "a commitment to liberty and limited government and an interest in the world of ideas." Oh yes, and $1,500 if you're solo and $2,600 for a couple, excluding air fare. When you're tired of thinking, Rancho Bernardo features five golf courses, two plaza swimming pools, seven hydro-spas, 12 tennis courts and a fitness center.

ANOTHER VACATION IDEA: If lounging with libertarians isn't for you, an option is the Progress and Freedom Foundation's sixth annual "Cyberspace and the American Dream" conference Aug. 22-24 in Aspen, Colo. Conference attendees can talk high tech with James Barksdale, former chief executive of Netscape, and Ira Magaziner, former chief of Internet policy for President Clinton. It costs $995 if you register before July 1 and $1,250 afterward (less if you work for Uncle Sam or a nonprofit).

STRAY THOUGHT: Uh-oh. Forget the Millennium Bug and start worrying about the Millennium Bang. A majority of Americans--57 percent--believe there will be even more bloodshed and violence in the 21st century than in this century, according to a recently released national survey conducted by the Chicago Council on Foreign Relations.