AUSTIN, Tex., March 29 — In 1999, Matthew Dowd became a symbol of George W. Bush’s early success at positioning himself as a Republican with Democratic appeal.

A top strategist for the Texas Democrats who was disappointed by the Bill Clinton years, Mr. Dowd was impressed by the pledge of Mr. Bush, then governor of Texas, to bring a spirit of cooperation to Washington. He switched parties, joined Mr. Bush’s political brain trust and dedicated the next six years to getting him to the Oval Office and keeping him there. In 2004, he was appointed the president’s chief campaign strategist.

Looking back, Mr. Dowd now says his faith in Mr. Bush was misplaced.

In a wide-ranging interview here, Mr. Dowd called for a withdrawal from Iraq and expressed his disappointment in Mr. Bush’s leadership.

He criticized the president as failing to call the nation to a shared sense of sacrifice at a time of war, failing to reach across the political divide to build consensus and ignoring the will of the people on Iraq. He said he believed the president had not moved aggressively enough to hold anyone accountable for the abuses at Abu Ghraib prison in Iraq, and that Mr. Bush still approached governing with a “my way or the highway” mentality reinforced by a shrinking circle of trusted aides.