The problem with instant history — or what Elisabeth Bumiller calls “an independent work of journalism” — is that insufficient time has passed to put things into perspective. So when writing a biography of Secretary of State Condoleezza Rice, with more than a year of her term to serve, it would be wise not to make judgments that could be overturned by events.

Musing in “Condoleezza Rice: An American Life” (Random House, 400 pages, $27.95) that Ms. Rice has enjoyed her share of successes and failures, Ms. Bumiller finds that “Iraq, her friends say, is likely to be her greatest failure of all,” and that Ms. Rice is “a pragmatist who for four overwhelming years got swept away by her devotion to the president and the hawks who held power.”

Although Ms. Rice has readily admitted that the invasion of Iraq has been marred by “tactical errors — thousands of them,” it would be rash today to try to judge whether the experiment in democracy in Iraq is a success. By all accounts, General Petraeus’s “surge” is working and Al Qaeda is being defeated.

By the time that full sovereignty is handed back to the Iraqis as President Bush concludes his term, the prospect of a long-lasting, peaceful settlement may seem more possible. If Iraq is not yet an unalloyed success, nor is it an irrevocable failure.

Ms. Bumiller goes on to record that Ms. Rice, like Secretary of State Colin Powell, was in charge of the neither invasion nor the administration of Iraq. Vice President Cheney pressed for the war and Defense Secretary Rumsfeld took control of it. It had been decided, with scant reference to Ms. Rice, that the Iraq war would follow the World War II model and that Defense, not State, would preside over Iraq’s reconstruction, as it had over the administration of defeated Germany. So why would Ms. Rice’s friends think that Iraq is her personal failure? The second charge, that Ms. Rice was out of her depth, buffeted around by tough men who would not allow her the full involvement in decision-making she desired, is more compelling. Throughout her service, Ms. Rice has often seemed unable to assert authority and unprepared to deal with new crises. Certainly Ms. Rice found it difficult to bring the competing demands of different departments together. And she was undoubtedly hindered in fulfilling the difficult job she had been given by that pair of old curmudgeons, Messrs. Cheney and Rumsfeld.

Some of the slights, and some of the awkward conversations, are cited here, though there are few, perhaps because Ms. Rice was outmaneuvered from the start. In the administration that Mr. Cheney sketched out for the new president, awaiting the Supreme Court’s decision over who won the White House, the vice president awarded himself more power than any in history. He was to take the lead in foreign policy and found in his old boss, Mr. Rumsfeld, a willing accomplice.

That decision having been made, Ms. Rice was destined to be a Cinderella in the White House, alternately ignored or abused. Often in this account she appears to have little more than a walk-on part in her own biography.

The secret of her initial elevation was that, beginning with his Mr. Bush’s presidential campaign, Ms. Rice taught him about foreign affairs in a way that did not patronize him. Or as Ms. Bumiller writes, “Rice made Bush feel sharper, particularly when she complimented him on his questions. Bush did not know many black people well, and it made him feel good about himself that he got along so easily with Rice.” One of the fascinating aspects of Ms. Rice’s rise is the way she so quickly became a Bush family intimate. Unmarried, smart, and good company, with only a piano in her Watergate apartment to keep her at home, she accepted Mr. Bush’s invitations to spend weekends with him.

They continue to watch sports on television together at Camp David and go on long walks in Crawford with the first lady. How exactly this improbable ménage works is a biographer’s dream, but gets little attention here.

As a consequence of her friendship, Ms. Rice was given an important post fresh from being provost at Stanford. Messrs. Cheney and Rumsfeld might be excused for being skeptical about how useful she would be in a crisis. The attacks of September 11, 2001, certainly took her by surprise, though the retelling here of when and what she knew, and whether she should have acted sooner, provides few fresh insights.

Even Ms. Rice herself seems uncertain of whether she was fully paying attention in her seven-month honeymoon before the terrorists struck. As she put it, “You lose three thousand Americans and you think, ‘Is there anything I should have done that I didn’t do?'”

What is clear is that the studious Ms. Rice was prone to confusion in the face of disaster. The hours and days immediately after September 11 were a testing time for everyone in the White House, but, according to Ms. Bumiller, Ms. Rice was “in an exhausted fog,” had “the relentless feeling that she needed to get things under better control,” and was “too overwhelmed by the day’s events to sleep.”

Later, when Ms. Rice was caught buying expensive shoes in Ferragamo’s Fifth Avenue store and laughing at a performance of “Spamalot” while the New Orleans population was submerged under the Katrina floods and official indifference, she found herself in a similar fog. Why was her behavior deemed irresponsible? “I just didn’t get it, frankly,” she confessed.

And when, in pursuit of the president’s goal to bring democracy to the Middle East, the Palestinian-Arabs voted for the terrorist group Hamas, Ms. Rice was again taken by surprise. She found out the result from the television news, while running in place in the gym, which is a neat metaphor for her obliviousness to the real world.

“I’ve asked why nobody saw [Hamas] coming,” she told the press. “It does say something about us not having a good enough pulse.” And it suggests that even on her own home ground, foreign affairs, Ms. Rice can have a treacherously tin ear.