WASHINGTON – White House political mastermind Karl Rove surrendered a key policy role Wednesday and press secretary Scott McClellan resigned in an escalation of a Bush administration shake-up driven by Republican anxieties.

Rove gave up his responsibilities as chief policy coordinator, a position he assumed just over a year ago that strengthened his influence over matters ranging from homeland security and domestic policy to the economy and national security.

The promotion had left him stretched too thin in the eyes of some officials, as the White House grappled with mounting problems.

With Wednesday’s change, Rove will be able to focus more on politics, fund-raising and big-picture thinking with the approach of the November congressional elections, officials said.

A major force in the administration from the start, Rove still is expected to have a big voice in policy but not the day-to-day oversight. Those responsibilities will shift to Joel Kaplan, who was promoted to deputy chief of staff from the No. 2 job in the White House budget office where he had served as Joshua Bolten’s lieutenant.

Bolten took over Friday as chief of staff with authority to do whatever he deemed necessary to stabilize Bush’s presidency, and he has moved quickly with changes.

With the Iraq war hanging over Bush, the White House has been rocked by mistakes and missteps – from an ill-fated Supreme Court nomination to a bungled response to Hurricane Katrina – that have resulted in the president’s plunge in the polls to the lowest point since he took office. Nervous Republicans told Bush he needed fresh people with new ideas.

McClellan, the press secretary for nearly three years, was the public face of the White House and a vulnerable target in an administration trying to show off new people. He had been bloodied by contentious press briefings and media criticism about an administration loath to give up information.

“The White House is going through a period of transition. Change can be helpful, and this is a good time and good position to help bring about change,” McClellan said, his voice choked with emotion as he stood alongside Bush outside the White House. “I am ready to move on.”