Washington ? Defense Secretary Donald Rumsfeld, architect of an unpopular war in Iraq, intends to resign after six stormy years at the Pentagon, Republican officials said Wednesday.

Officials said Robert Gates, former head of the CIA, would replace Rumsfeld.

The development occurred one day after midterm elections that cost Republicans control of the House, and possibly the Senate, as well. Surveys of voters at polling places said opposition to the war was a significant contributor to the Democratic victory.

President Bush was expected to announce Rumsfeld’s departure and Gates’ nomination at an afternoon news conference. Administration officials notified congressional officials in advance.

Last week, as he campaigned to save the Republican majority, Bush declared that Rumsfeld would remain at the Pentagon through the end of his term.

Rumsfeld, 74, was in his second tour of duty as defense chief. He first held the job a generation ago, when he was appointed by President Ford.

Gates is the president of Texas A&M University and a close friend of the Bush family. He served as CIA director for Bush’s father from 1991 until 1993.

Gates first joined the CIA in 1966 and served in the intelligence community for more than a quarter century, under six presidents.

His nomination must be confirmed by the Senate.

Whatever confidence Bush retained in Rumsfeld, the Cabinet officer’s support in Congress had eroded significantly. Rep. Nancy Pelosi, D-Calif., the House speaker-in-waiting, said at her first post-election news conference that Bush should replace the top civilian leadership at the Pentagon.

And Senate Majority Leader Bill Frist, who had intervened in the past to shore up Rumsfeld, issued a statement saying, “Washington must now work together in a bipartisan way – Republicans and Democrats – to outline the path to success in Iraq.”