Secretary of State Colin L. Powell announced his resignation yesterday, ending four years of battles with Vice President Cheney and Defense Secretary Donald H. Rumsfeld over the course of U.S. foreign policy.

Administration officials said Powell, whose departure was announced by the White House along with three other Cabinet resignations, will be replaced by national security adviser Condoleezza Rice, one of President Bush's most trusted confidantes. Rice will be replaced by her deputy, Stephen J. Hadley, administration officials said. The Rice and Hadley announcements will be made as soon as today, the officials said.

Republican officials said the selection of Rice reflects Bush's determination to take personal control of the government in a second term, especially departments and agencies that he felt had undermined him in the first four years. Powell's departure is also a victory for conservatives, removing the administration's most forceful advocate for negotiations and multilateral engagement on such issues as Middle East peace and curbing nuclear activities in Iran and North Korea.

A White House official said Powell, who helped persuade Bush to seek approval from the United Nations before invading Iraq, indicated to the president weeks or months before Nov. 2 that he planned to leave soon after the election. But one government official with personal knowledge of the situation said Powell had second thoughts and had prepared a list of conditions under which he would be willing to stay. They included greater engagement with Iran and a harder line with Israeli Prime Minister Ariel Sharon.

Powell and Bush met at the White House on Friday, the date on the secretary's letter of resignation. Details of the meeting could not be learned, but White House officials said the secretary was not asked to stay. A senior State Department official said Powell made no demands of the president and gave no hints that he might stay, an account echoed by White House aides.

Bush issued a statement yesterday calling Powell "one of the great public servants of our time" and praising "the calm judgment and steady resolve he has brought to our foreign policy."

In an appearance yesterday afternoon in the State Department briefing room, Powell said he will stay "a number of weeks or a month or two, as my replacement goes through the confirmation process." He described his departure as long in the making.

"In recent weeks and months, President Bush and I have talked about foreign policy and we've talked about what to do at the end of the first term," Powell said. "It has always been my intention that I would serve one term. And after we had had a chance to have good and fulsome discussions on it, we came to the mutual agreement that it would be appropriate for me to leave at this time."

Foreign policy experts predicted that Powell's resignation, and Rice's ascension, could result in a more coherent message from the Bush administration. Kenneth Adelman, a conservative foreign policy specialist, worked with Powell during the Reagan administration. "Powell is a wonderful, wonderful person," he said. "The sad part about this episode in this Bush administration is fundamentally he and the president disagreed on central issues on national security and foreign policy."

Rice, by contrast, "certainly shares Bush's views and has learned better than anyone what Bush's views are," Adelman said. "You are not going to have that split in a second term."

The White House announced Powell's departure along with the resignations of three other Cabinet members -- Education Secretary Roderick R. Paige, Agriculture Secretary Ann M. Veneman and Energy Secretary Spencer Abraham. Their departures -- along with the earlier resignations of Attorney General John D. Ashcroft and Commerce Secretary Donald L. Evans, and the likely departure of Homeland Security Secretary Tom Ridge for a lucrative post in private industry -- mean that Bush will replace about half of the 15 heads of executive departments for his second term.

Administration officials said more departure announcements are likely, including one from Transportation Secretary Norman Y. Mineta, the lone Democrat in the Cabinet.

Three of the departments will be headed by officials who are White House staff members and close to Bush: Ashcroft is being replaced by White House counsel Alberto R. Gonzales, and Paige is likely to be replaced by Bush domestic policy adviser Margaret Spellings. Both Gonzales and Spellings worked for Bush in Texas. A Bush aide said the goal is to signal a Cabinet "that clearly takes a team approach."

The impact, according to one Republican close to the administration, will be to "control the government, not just the White House" in the second term and to give the president "an enhanced ability to control the broad sweep of policy undertaken in the second term."

White House press secretary Scott McClellan suggested that the resignations were a mix of voluntary and involuntary. "The president has the right to make decisions about who makes up his team for a second term," he said.

Administration officials said Rumsfeld, the other most prominent member of Bush's war cabinet, will continue to run the Pentagon for the foreseeable future.

"The decision was made to keep Rumsfeld and drop Powell because if they would have kept Powell and let [the Rumsfeld team] go, that would have been tantamount to an acknowledgment of failure in Iraq and our policies there," one government official said, requesting anonymity to speak more candidly. "Powell is the expendable one."

Rumsfeld was asked during a news conference yesterday if he had submitted his resignation to Bush. "I haven't discussed that with him at all, in writing or orally," he said. Rumsfeld did not say whether he had discussed the matter with Cheney.

Powell has consistently shown up in polls as the administration's most popular figure. He was accorded movie-star treatment by mammoth crowds in 1995 during the book tour for his autobiography, "My American Journey." He kept his party affiliation secret during his military career, and both parties sought him as a presidential candidate. He finally said he was a Republican who supports affirmative action and abortion rights.

When Bush was Texas governor and running for president, his flirtations with Powell -- who was chairman of the Joint Chiefs of Staff under President George H.W. Bush during the Persian Gulf War -- bolstered his case that he could handle foreign policy. Powell was the first African American to become secretary of state, and Rice will be the first black woman in that office.

During his tenure as chairman of the Joint Chiefs, Powell was known for the Powell Doctrine, which called for the use of overwhelming force for a quick, clean victory and minimal cost in American lives. But as secretary, he was repeatedly outmaneuvered by the Pentagon and was never able to persuade the administration to adopt that approach in Iraq, or to accept the State Department's plans for post-invasion occupation in Iraq.

Powell brought together representatives of the United Nations, the European Union and Russia to design the "road map" for peace between Israelis and Palestinians, but has not been able to persuade the White House to use the muscle necessary to implement it. Powell is also credited with improving U.S. relations with Russia and China, helping to persuade Libya to give up weapons of mass destruction, pushing the administration to increase its commitment to the international fight against AIDS, and promoting the administration's Millennium Fund, which linked U.S. aid to democratic reform.

Powell, 67, objected in private to the timing of the invasion of Iraq and to the way the United States prepared for it. But in what friends see as irony, one of the most memorable appearances of his tenure was his February 2003 presentation to the United Nations, televised live worldwide, in which he used satellite photos and other evidence -- some of it since discredited -- to make the case for using force against Iraqi president Saddam Hussein.

Kenneth M. Duberstein, chief of staff to President Ronald Reagan and a friend of Powell's, said the secretary's decision "is about him getting his life back again."

"He wants to be able to tinker under the hood and go to hardware stores and eat rotisserie chicken, just like he used to," Duberstein said.

Sen. Chuck Hagel (R-Neb.) said in a statement lamenting Powell's resignation that he has "commanded international respect" and "leaves the State Department as still the most respected, most trusted, and most popular leader in America today."

Staff writer Glenn Kessler contributed to this report.

Secretary of State Colin L. Powell, speaking to the media at the State Department after resigning, is the top administration official to announce his departure since President Bush's reelection. Secretary of State Colin L. Powell, with President Bush in 2002, met with the president and was not asked to stay, White House officials said.Roderick R. Paige has resigned his position as President Bush's education secretary.