Political leaders from both parties now agree that the American people need to know by September whether the latest escalation in Iraq is working. Many lawmakers will formulate their position on the basis of a coming report from Gen. David Petraeus, commander of the multinational force, to the president. Unfortunately, based on behavior in his last command in Iraq and the manner in which he received his current position, Petraeus is not a reliable source for an unbiased assessment.

On Sept. 26, 2004, about six weeks before the presidential election, in which the deteriorating situation in Iraq was an increasingly important issue, then Lt. Gen. Petraeus published a misleading commentary in the Washington Post. In that article, Petraeus, who was then in charge of training Iraqi security forces, spoke glowingly about the tangible progress that those forces were making under his tutelage. According to Petraeus, more than 200,000 Iraqis were performing a wide variety of security missions; training was on track and increasing in capacity; 45 Iraqi National Guard battalions and six regular Army battalions were conducting operations on a daily basis; and by the end of November 2004, six more regular Army battalions and six additional Intervention Force battalions would become operational.

Because Bush administration policy at that time was that "we will stand down when they stand up," this article, in effect, conveyed to the American electorate that the Iraqis were, indeed, standing up, and, therefore, there was light at the end of the tunnel for the Iraqi quagmire.

If Petraeus wrote on his own initiative, he was injecting himself improperly into a political campaign. If he was encouraged or even allowed to do this by his civilian superiors, he was allowing himself to be used for partisan political purposes.

Even assuming that Petraeus would not repeat his 2004 performance, can we really expect him to be objective about the current situation when the president consistently reminds us that the surge is Petraeus' strategy? In a speech in early May defending the surge, President Bush mentioned Petraeus by name no less than 12 times and stated that the "best messenger for the surge" is David Petraeus. Bush has gone so far as to argue that when the Senate confirmed Petraeus to head the operation in Iraq, it was, in effect, approving the current strategy.

Asking Petraeus to assess the situation in September might be asking him - if the evidence pointed in that direction - to say that his whole counterinsurgency strategy was wrong. If the evidence is not clear, he would most likely cherry-pick data by pointing out, as he already has, that sectarian violence is down in Baghdad, while ignoring such inconvenient truths as the increase in suicide bombings or the rise in deaths of American soldiers and contractors.

Was Gen. William Westmoreland ever objective about the attrition strategy in Vietnam or Gen. Douglas MacArthur about the Chinese intervention in Korea?

Most likely, Petraeus would say that he needs more time, that not all of the extra troops arrive until June. He already has indicated that he will not have anything definitive by September. In fact, Petraeus and his commanders have said the surge must last until spring 2008. Moreover, the Pentagon has alerted four National Guard brigades and 10 more active brigades for deployment to Iraq, so that the escalation can be maintained through the end of 2008.

Another complicating fact is that one purpose of the surge was to buy time for Iraqi reconciliation. Suppose that violence is down, but that the Iraqis have not taken such steps as passing the oil law or providing for provincial elections. Maj. Gen. Richard Lynch, current commander of the Third Infantry Division, noted that even if security does improve, he doesn't think there will be significant progress on the government side between now and then.

The answer is to have an independent assessment by an outside group, like the Iraq Study Group, but not including members of that group who might also have an ax to grind. The House and Senate each should appoint one member and the administration another. Only then can we be sure that we will get an unbiased assessment, and that this country will come to grips with the real situation in Iraq.

Lawrence J. Korb (lkorb@americanprogress.org) is a senior fellow at the Center for American Progress and a senior adviser to the Center for Defense Information. He was a assistant secretary of defense in the Reagan administration.