But during those two terms in the White House, Mrs. Clinton did not hold a security clearance. She did not attend National Security Council meetings. She was not given a copy of the president’s daily intelligence briefing. She did not assert herself on the crises in Somalia, Haiti and Rwanda.

And during one of President Bill Clinton’s major tests on terrorism, whether to bomb Afghanistan and Sudan in 1998, Mrs. Clinton was barely speaking to her husband, let alone advising him, as the Lewinsky scandal sizzled.

An interview with Mrs. Clinton, conversations with 35 Clinton administration officials and a review of books about her White House years suggest that she was more of a sounding board than a policy maker, who learned through osmosis rather than decision-making, and who grew gradually more comfortable with the use of military power.