Last month, when the Democrats of the 107th Congress needed to know how President Bush's proposed tax cut would affect the economy, they called Lawrence H. Summers.

Now, the former secretary of the Treasury is preparing to make the transition back to academia from the Washington world he has inhabited since his first appointment to the Clinton administration in 1993.

Summers's colleagues in Washington say that he was a brilliant economic administrator who was critical in the development of the Clinton administration's financial policies. But they say that though Summers is a Democrat, his competence and lack of partisanship have earned him the admiration of Republicans and Democrats alike.

When Summers left Harvard in 1993 for a post at the Treasury Department, some thought he would not last long outside the world of academia and inside the political world of Washington.

"What was so impressive about Larry's performance in Washington is that people at first predicted that he would not be able to translate his academic brilliance into effectiveness in the political arena, and they proved to be dead wrong," said Gene Sperling, former National Economic Advisor and former director of the National Economic Council.

While some have called the pairing of Summers and his predecessor Treasury Secretary Robert E. Rubin as an odd one because of their differing styles of leadership, the two men became fast friends. Associates of the two men say they were able to draw off of each others' strengths, and made a formidable team heading up Clinton's economic issues.

"He became a skilled advocate for the positions of the administration, and learned to be at ease in settings as diverse as meeting with foreign heads of state or sitting and getting yelled at by Cokie Roberts," said former White House Chief of Staff John D. Podesta.

David P. Ellerman, one of Summers' colleagues at the World Bank, said that the transition from academic to administrator and Washington insider took one major readjustment.