By Paul Reynolds
BBC News website world affairs correspondent
Underlying President Bush's change of rhetoric over Iraq lies an acceptance that the US and other coalition forces will not defeat the insurgency by themselves.
Lessons should be drawn from Vietnam - Nixon defence secretary
The emphasis has therefore shifted towards stressing the need for Iraqis to do the job, which should thereby enable the Americans to start withdrawing forces.
Whether it works or not is an entirely different matter.
We have been past so many milestones along this road: the fall of Saddam; the appointment of the provisional government; the capture of Saddam; the January elections; the transitional government, the referendum, etc.
At each milestone the way ahead was clear, we were told. It proved not to be so.
For a start there is the questionable ability of the Iraqi forces.
And then there is the strength of the insurgency - a word, by the way, US Defence Secretary Donald Rumsfeld says should not be used. He has suggested "enemies of the legitimate Iraqi government".
The change has also been driven by two other important factors - first, domestic American unease about the war and second, the forthcoming elections in Iraq designed to produce a constitutional government.
The first requires the president to steady the ship with a display of confidence, and the second enables him to place responsibility on an Iraqi government for prosecuting the war.
But those who think that Mr Bush is about to "declare victory and leave", as Senator George Aiken once suggested for Vietnam, are likely to be disappointed.
Mr Bush is a resolute character and does not want to go down as the man who lost Iraq.
Indeed all the signs are that he feels he is on a mission.
And that means that if US forces are felt to be needed, they will be provided.
An interesting parallel from the Vietnam era has recently been drawn that is both an example and a warning - an example of what to try and a warning of what might happen if it does not work.
Of course, historical parallels are often dangerous, but the author in this case has some experience.
He is the former defence secretary under Richard Nixon, Melvin Laird, and in an article for Foreign Affairs magazine he proposes the same policy in Iraq that he tried in Vietnam - the "Iraqization" of the conflict.
It is not a new policy as such but the eggs are being heavily laden into this basket right now.
"We need to put our resources and unwavering public support behind a program of 'Iraqization' so that we can get out of Iraq and leave the Iraqis in a position to protect themselves.
"The Iraq war should have been focused on Iraqization even before the first shot was fired. The focus is there now, and Americans should not lose heart," Mr Laird wrote.
This was tried, he said, in South Vietnam. He claims that it would have worked if Congress had not stopped funding the government in Saigon not long after the US had withdrawn its own forces.
"The truth about Vietnam that revisionist historians conveniently forget is that the United States had not lost when we withdrew in 1973," he said.
"In fact, we grabbed defeat from the jaws of victory two years later when Congress cut off the funding for South Vietnam that had allowed it to continue to fight on its own."
The claim that South Vietnam might have held off the North is a controversial one.
Mr Laird himself acknowledges that the funding commitment by both the United States and the Soviet Union was technically for replacement weapons for their clients. But nobody in Washington could have thought that Moscow would live up to this, and it did not.
The war was probably lost sooner or later anyway and the Americans must have known it.
But his point as applied to Iraq lends support to the policy of this administration.
"The United States should not let too many more weeks pass before it shows its confidence in the training of the Iraqi armed forces by withdrawing a few thousand US troops from the country. We owe it to the restive people back home to let them know there is an exit strategy, and, more important, we owe it to the Iraqi people," he said.
Might US ground troops be replaced by more US airpower?
Another interesting article directly relating to how the US might withdraw some troops is in the New Yorker magazine. It is from the veteran Washington reportorial digger Seymour Hersh.
He raises the prospect of the US compensating for withdrawal by providing more air support for the Iraqis.
"A key elements of the drawdown plans, not mentioned in the President's public statements, is that the departing American troops will be replaced by American airpower. Quick, deadly strikes by US warplanes are seen as a way to improve dramatically the combat capability of even the weakest Iraqi combat units," Hersh wrote.
However, the policy would bring the added danger of air strikes against the wrong targets and raises the question of whether US troops or Iraqis would direct the aircraft. Some US officers do not want Iraqis ordering their planes when and where to strike.
This shows that thinking is going on about how to reduce the American profile in the war, without cutting and running.