By John M. Donnelly, CQ Staff

Congressional Democrats on Tuesday questioned whether the U.S. commander in the Mideast was forced to resign because he differed with President Bush’s military and diplomatic policies.

Tuesday’s announcement of the departure of Adm. William J. Fallon, commander of U.S. Central Command, could become an exhibit in the Democrats’ case that Bush has regularly defied the advice of his military commanders and could do so again if he were to attack Iran.

Fallon and Defense Secretary Robert M. Gates called the admiral’s resignation his own decision. But it comes after publication this month of an article in Esquire magazine depicting Fallon as the only one of Bush’s security advisers who stood between the president and war with Iran over that country’s nuclear program.

Senate Majority Leader Harry Reid , D-Nev., called Fallon’s resignation “yet another example that independence and the frank, open airing of experts’ views are not welcomed in this administration. It is also a sign that the administration is blind to the growing costs and consequences of the Iraq War, which has so damaged America’s security interests in the Middle East and beyond.”

House Speaker Nancy Pelosi , D-Calif., called Fallon’s departure “a loss for the country, and, if it was engineered by the administration over policy differences, that loss is compounded significantly.”

Predictably, the Republican response was more muted.

John W. Warner of Virginia, the longest-A-serving Republican on the Senate Armed Services Committee, said: “If it was his judgment that relationships in the chain of command through and up to the president were not working in the best interests of our nation, he mustered the courage to step aside.”

Fallon is said to have differed with the U.S. commander in Iraq, Gen. David H. Petraeus, and Bush over the wisdom of maintaining high troop levels in Iraq at substantial cost to military readiness.

“Recent press reports suggesting a disconnect between my views and the president’s policy objectives have become a distraction at a critical time and hamper efforts in the Centcom region,” Fallon said in a statement. “And although I don’t believe there have ever been any differences about the objectives of our policy in the Central Command area of responsibility, the simple perception that there is makes it difficult for me to effectively serve America’s interests there.”

Bush, in a statement, lauded Fallon: “During his tenure at Centcom, Admiral Fallon’s job has been to help ensure that America’s military forces are ready to meet the threats of an often-troubled region of the world, and he deserves considerable credit for progress that has been made there, especially in Iraq and Afghanistan.”

Gates told reporters it was a myth that Fallon did not support the president’s Iran policy, which he described as dealing with Iran primarily through a variety of non-military means.

“I don’t think there were differences at all,” Gates said.

Fallon, 63, is a former vice chief of the Navy and chief of U.S. Pacific Command who has run Central Command for nearly a year. Gates told reporters that Fallon’s deputy, Army Lt. Gen. Martin Dempsey, will take over temporarily after Fallon leaves.

Some Democrats demanded more information about Fallon’s exit.

“Admiral Fallon was a voice of reason in an administration which has used inflammatory rhetoric against Iran,” said Hillary Rodham Clinton of New York, a member of the Senate Armed Services Committee who is seeking the Democratic presidential nomination. “I am asking that the Senate Armed Services Committee hold hearings into the circumstances surrounding his departure.”

Committee Chairman Carl Levin , D-Mich., said: “I can only hope that the decision to retire was his own.”

Republicans focused mainly on praising Fallon’s service.

“Under Admiral Fallon’s leadership at Central Command, the situation in Iraq has improved dramatically,” said John McCain , R-Ariz., the all-but-certain GOP presidential nominee. “I am confident President Bush will act promptly to select the right person to lead Central Command at this critical juncture.”