Education Secretary Rod Paige (search) will resign his Cabinet position, FOX News has confirmed.

A Texan like Bush, Paige, 71, came to prominence as an award-winning superintendent in Houston before becoming secretary in a time of huge change in federal education policy. An outspoken defender of demanding more from schools, he has been the public face behind No Child Left Behind (search), the law at the center of Bush's domestic agenda.

White House press secretary Scott McClellan declined to speculate about the Cabinet position.

Paige would be the third member of the Bush Cabinet to make plans to leave since the president won a second term. Attorney General John Ashcroft (search) and Commerce Secretary Don Evans (search) also are departing.

Paige has not formally handed in his resignation, an official who has talked to Paige about his plans told the Associated Press.

The administration official said Paige is content to move on after overseeing Bush's education agenda for four years. The official declined to be identified because Paige has yet to resign.

A leading candidate to replace Paige is Margaret Spellings, Bush's domestic policy adviser who helped shape his school agenda when he was the Texas governor. Spellings has a keen interest in schools and may want the Cabinet-level education job.

Paige has presided over the biggest federal shakeup to education in a generation, a law demanding that schools show improvement among all students, regardless of race or wealth. Paige, who grew up in segregated Mississippi, puts No Child Left Behind in the category of Brown v. Board of Education, the landmark case that ended separating schools by race.

Yet Paige has had rocky moments, with none more glaring than when he called the National Education Association a "terrorist organization" in a private meeting with governors.

He apologized but maintained that the NEA, the nation's largest teachers union, uses "obstructionist scare tactics" in opposing the law. The union called for his resignation.

Many education followers have suggested Bush would seek a change at the top, and that Paige would be content to go after capping his public service career in Washington. But in recent days, some close to Paige have said he's seemed eager to carry on the oversight of the law.

"I talked to him before he gave his speech at the Republican convention, and he seemed to be enjoying his job immensely," Williamson Evers, a Hoover Institution research fellow, said recently. Evers is an informal adviser to the White House and the Education Department.

Sandy Kress, a former senior education adviser to Bush, said Friday that Paige "has spoken with great moral authority about the goals of No Child Left Behind. He feels it personally. He brought a history, he brought experience, and I think he brought a great commitment to the cause."

Paige is eying other work opportunities and does not plan to retire, the administration official said.

From college dean and school superintendent to the nation's education chief, Paige has built a career on the belief that education equalizes opportunity. As his tenure unfolded, he chose increasingly forceful terms in defending Bush's agenda.

He compared critics of the administration's education overhaul to those who opposed school desegregation 50 years ago, saying both will fall on the wrong side of history.

And Paige said private-school vouchers in the District of Columbia amount to nothing short of "emancipation" for hundreds of poor and minority students, allowing them to "throw off the chains of a school system that has not served them well."

Still, Paige could have done more had the White House given him more freedom, said William Bennett, who served as education secretary under President Reagan.

"I think he's a better man than they even know," Bennett said in a recent interview. "He's an in-the-trenches reformer."

Other possible replacements for Paige are Eugene Hickok, the deputy education secretary, and Raymond Simon, assistant secretary over elementary and secretary education. Spellings, whose name has surfaced most often as Paige's successor, is responsible for creating and overseeing White House policy on education, health, labor and other domestic issues.

The Associated Press contributed to this report.