WASHINGTON – Margaret Spellings, who helped write the most demanding education law in a generation, pledged yesterday to address “horror stories” about how it’s working if she becomes the country’s top schools leader.

Ms. Spellings, President Bush’s nominee for education secretary, received praise and friendly questions for the most part at her confirmation hearing before the Senate Education Committee.

The committee unanimously recommended Senate confirmation, which is expected soon.

But she was pushed to explain how she would enforce No Child Left Behind, the law she helped engineer as Mr. Bush’s domestic policy chief and one that has exasperated many educators.

The law requires yearly gains among all students, regardless of race, income, or English ability. Schools that receive poverty aid face penalties if they fall short.

It is seen as an aggressive response to a national problem, as less than a third of fourth-graders and eighth-graders can read and perform math up to federal standards.

Many education leaders, however, say they struggle with the law, from getting top qualified teachers in every class to finding room for students who are promised transfers.

Reaching out to teachers and parents, Ms. Spellings said: “We must stay true to the sound principles of leaving no child behind. But we in the administration must engage with those closest to children to embed these principles in a sensible and workable way.”

After senators took turns explaining their states’ problems with the law, Ms. Spellings acknowledged, “Obviously, this is a theme here.”

“None of us wants to tip the boat over, if you will, with these horror stories,” Ms. Spellings said. “We in the administration are committed to making this law workable.”

Ms. Spellings, 47, entered her hearing on strong footing, having won praise from both parties as a respected policy-maker and fair negotiator with Congress.

Ms. Spellings was Mr. Bush’s education adviser when he was Texas governor and then joined him in the White House.

“I don’t think anyone has a better understanding of the president’s position [on education],” said Senator Enzi, a Wyoming Republican who is chairman of the Committee on Health, Education, Labor, and Pensions. “You will now be in a perfect position to promote his agenda.”

Senator Kennedy of Massachusetts, the ranking Democrat, said: “I hope it’s not the kiss of death for the right wing, but I’ve welcomed the opportunity to work with Margaret Spellings … I think she’s an inspired choice to be secretary of education.”

Ms. Spellings outlined Mr. Bush’s agenda for his second term: requiring additional state testing in the high school grades, beefing up the academic rigor of vocational programs, and reshaping college aid to help nontraditional students.

The testing idea may well run into opposition, and any spending proposals face a fight because of a federal budget crunch.

Ms. Spellings signaled that she may seek to do more to hold colleges accountable, an idea floating in Congress.