One of the more intriguing speculations about Barack Obama's approaching administration is how he will deal with the military brass, which has been under orders for more than five years to achieve "victory" in Iraq.

Gen. David Petraeus, the chief strategist of the surge opposed by the new president, is now in charge of the Central Command that runs the American presence in the Middle East. Something obviously will have to give regarding that ill-defined objective of the departing Bush regime.

Obama's campaign pledge to withdraw all U.S. combat troops from Iraq in 16 months after taking office is a lot more ambitious than the outlook suggested either by Petraeus or his superior, Adm. Michael Mullen, the chairman of the Joint Chiefs of Staff.

There is no ambiguity in the Constitution's stipulation that the president "shall be commander in chief of the Army and Navy of the United States." A military leader who may disagree with him may grouse about his policies and decisions, but his only recourse is to do the president's bidding or offer his resignation.

In the most famous clash of wills between a president and a military leader, Harry Truman relieved Gen. Douglas MacArthur of command in the Korean War after the general had openly undercut the president's efforts to negotiate a truce with the communist Chinese.

In that episode, MacArthur essentially issued an ultimatum to the Chinese to quit or be annihilated, violating a gag order by Truman to stay out of political and diplomatic overtures, and Truman fired him. Nothing of the sort is likely to occur between Obama and Petraeus, who already share an objective of establishing a viable democratic regime in Iraq and then leaving.

But Obama will be the second Democratic president in 16 years to become commander in chief without previous military experience and a history of opposition to American involvement in an undeclared war. Bill Clinton's situation was complicated by the fact that he had taken actions to avoid being drafted during the war in Vietnam, creating ill will among many who served there. Obama never faced the possibility of being called up.

Clinton also unwisely injected himself into a touchy military argument in the first days of his presidency by proposing to lift the existing ban on gays serving in the armed forces. It was a pledge he had made in his presidential campaign, but one for which there was no notable clamor for swift action among the electorate. The proposal caused an uproar in the military and earned Clinton much hostility among the Pentagon brass.

Obama as a candidate steered clear of such similarly controversial positions affecting the military. While he has committed himself to ending the war in Iraq and focusing on the U.S. military mission in Afghanistan, his military positions have lately been overshadowed by the nation's financial crisis. He may still may face trying times with his military leadership, but he doesn't begin with the baggage that burdened Clinton then.

Clinton's controversial decision to kick off his administration by plunging into the gays-in-the-military fight argument provided a lesson to Obama to choose as his first initiatives proposals more likely to win general public acceptance. His declared priority of dealing with the financial and bank crisis is likely to buy him considerable time in weighing his options, in consultation with his military leaders, on the most achievable timetable for getting out of Iraq.

Even before the implosion of the banking and investment industry, the disintegration of the economy had eclipsed the two wars as the prime concern of voters in all the public-opinion polls. And two of three Americans shared Obama's view that the war in Iraq was a mistake.

The president-elect has already taken pains to advertise his efforts to cope with the turbulence on Wall Street in terms of meeting the needs of America's middle class on Main Street, including his proposed tax cut for 95 percent of working Americans. Had Clinton, an earlier champion of the middle class, started his presidency that way, there's no saying how it might have turned out.

Jules Witcover's latest book, on the Nixon-Agnew relationship, "Very Strange Bedfellows," has just been published by Public Affairs Press. Reach him at juleswitcover@earthlink.net.