By ROBERT BURNS, The Associated Press

WASHINGTON -- The inevitability of surprise -- be it North Korea's invasion of South Korea in 1950 or Iraq's invasion of Kuwait in 1990 -- is a guiding principle of the Bush administration's evolving strategy on national security, Defense Secretary Donald H. Rumsfeld said Wednesday.

In a closed-door session with the House Armed Services Committee, Rumsfeld told members he has made no decisions yet on strategy and other fundamental issues he has taken under review.

In an indication the strategy could take many more weeks to develop, Rumsfeld said he hoped Congress would hold hearings on questions such as whether the United States should abandon the principle that the military must be prepared to fight two major regional wars almost simultaneously.

He said he has not decided whether such a change would be wise or whether he favored an alternative approach.

To underscore his point about the importance of preparing for the unexpected, Rumsfeld gave the panel members copies of the forward to Roberta Wohlstetter's 1962 book, "Pearl Harbor: Warning and Decisions."

In it, Harvard's Thomas C. Shelling wrote that the challenge for the U.S. military in preparing for the next crisis is to avoid thinking that the most familiar threat is also the most probable.

In that vein, Rumsfeld said a key theme of Bush's strategy will be preparing for the unexpected.

Rumsfeld noted that during Dick Cheney's confirmation hearing to be defense secretary in 1989, there was not a single mention of Iraq. A year later, the Iraqi army caught the world by surprise by invading Kuwait, triggering the biggest American military operation since the Vietnam war.

Rumsfeld is considering questions not only about how and when to use force, but also how big the military should be, how it should be organized and for what missions.

The session in the House lasted about two hours and 15 minutes. Rep. Bob Stump, the Arizona Republican who leads the House Armed Services Committee, told reporters it was a "very productive meeting."

A similar closed-door meeting with the Senate Armed Services Committee was postponed until today.

Rumsfeld has come under growing criticism -- privately by some military officers, more publicly by several lawmakers -- for sharing too little of what he is doing inside the Pentagon. His sessions on Capitol Hill are meant to assure members that no decisions have been made, that he wants to work with Congress on these issues and that he welcomes oversight and scrutiny.

He told the House committee that the administration had not decided how big the 2002 defense budget should be, nor how to approach the politically touchy issue of closing military bases, according to an official familiar with the discussion who spoke on condition of anonymity.

This official said Rumsfeld listed what he views as the major challenges ahead, including modernizing Pentagon business practices, recruiting and retaining enough good people, improving the quality of life for people in uniform and developing trust between the Pentagon and Congress.

On Friday, President Bush is giving the commencement address at the U.S. Naval Academy in Annapolis, Md., where he is expected to discuss military issues but not make public a new national security strategy, officials said.