Mr. Bush, who has a reputation for sticking with allies through tough times, has shown two longtime advisers to the door and scaled down the role of his chief political strategist.
Washington is wondering, who's next? Treasury Secretary John Snow's name is the first mentioned by Republican insiders.
The latest moves in a widening shake-up came Wednesday when Karl Rove, the architect of Mr. Bush's rise to the White House and his re-election, surrendered a key policy role and press secretary Scott McClellan resigned. The announcements followed the March 28 resignation of White House chief of staff Andy Card, who left to calm Republican anxieties that Mr. Bush's presidency was going down a troubled path.
Rove gave up his responsibilities as chief policy coordinator, a position he assumed just over a year ago and 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.
Sources tell CBS News there was a general feeling that Rove had way too much on his plate, and that he had a meeting with the president in which Mr. Bush said to him, "Number one, I want you to focus on retaining Republican control of the Congress.' And, number two, 'I want you to focus on those big issues, like immigration reform, like tax cuts, those issues that are going to define the rest of my presidency.'"
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 Mr. Bush's presidency. He has moved quickly to make changes.
With the Iraq war hanging over Mr. 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 Mr. Bush he needed fresh people with new ideas.