It would not be "a nervous reaction by Washington politicians to poll results in the media".
Bush made the trip to hold a "war council" with senior US and Iraqi officials in advance of the report by General David Petraeus, the US commander in Iraq, on the success of the "surge" in US troop levels.
"You are denying al-Qaeda a safe haven from which to plot and plan and carry out attacks against the United States of America," he told US soldiers who roared their approval.
He landed in Anbar province, once a Sunni Arab fighter stronghold but now seen by the US military as a success story.
The drop in violence in Anbar has been attributed to Sunni Arab leaders joining forces with the US military to combat al-Qaeda fighters.
However Marwan Bishara, Al Jazeera's senior political analyst, says it would be political suicide for Bush to begin a real troop withdrawal in Iraq.
"The US cannot withdraw from the Iraq because it will be humiliating for the American empire."
Bush was accompanied on Monday's trip by Condoleezza Rice, the secretary of state, and Stephen Hadley, Bush's national security adviser.
He also met Nuri al-Maliki, the prime minister, who some US politicians have called on to quit over his failure to develop a national reconciliation programme.
Officials on hand
Waiting for Bush at the base were Robert Gates, the defence secretary, and General Peter Pace, the chairman of the joint chiefs of staff.
|Bush met US soldiers at the al-Asad base|
in Anbar during his visit on Monday [AFP]
Admiral William Fallon, the commander of US forces in the Middle East, and General David Petraeus, the US commander in Iraq, were also at the base to meet Bush.
Geoff Morrell, a Pentagon spokesman, said: "This is the last big gathering of the president's military advisers and the Iraqi leadership before the president decides on the way forward."
Bush is on his way to Australia to attend the Asia Pacific Economic Co-operation forum summit.
His arrival coincided with a British military pullback from its base in the centre of the southern Iraqi city of Basra.
Next week, Petraeus and Ryan Crocker, the US ambassador in Baghdad, are to testify before the US Congress.
They will report on the impact of Bush's decision to send an additional 30,000 US soldiers to Iraq, a move that increased force numbers to 160,000.
Their assessment of the conflict, along with a progress report the White House must hand legislators by September 15, is expected to determine the next phase of US military involvement in Iraq.
Amid a rising US death toll, currently estimated at 3,700, and growing calls from the Democratic Party for a troop withdrawal, Bush is under pressure to decide whether to give al-Maliki more time to find a political solution to the crisis.