Karl Rove, President Bush's longtime political adviser, is resigning as White House deputy chief of staff effective Aug. 31, and returning to Texas, marking a turning point for the Bush presidency.

Mr. Rove's departure removes one of the White House's most polarizing figures, and perhaps signals the effective end of the lame duck administration's role in shaping major domestic policy decisions, where the former Texas political consultant was a driving force. Mr. Rove revealed his plans in an interview with Paul Gigot, editor of The Wall Street Journal's editorial page. (See related commentary.)

President Bush made a formal announcement Monday morning. "Karl Rove is moving on down the road," Mr. Bush said, appearing grim-faced on the White House's South Lawn with Mr. Rove at his side. "We've been friends for a long time and we're still going to be friends... I'll be on the road behind you here in a bit," he said.

"I'm grateful to have been a witness to history. It has been the joy and the honor of a lifetime," said Mr. Rove, his voice quivering at times. "But now is the time... At month's end," Mr. Rove said, "I will join those whom you meet in your travels, the ordinary Americans who tell you they are praying for you."

After a lengthy hug from Mr. Bush and then his wife, Laura, Mr. Rove joined them on the president's helicopter. Mr. Rove, his wife and their son were flying with Mr. Bush on Air Force One to Texas, where the president is vacationing.