Congressional Democratic leaders are aggressively strategizing a new offensive against the Bush administration's management of the Iraq war as more and more anti-war lawmakers publicly acknowledge successes ahead of a key White House progress report.

Aware of the trouble Iraqi progress could mean for Democrats at home — House Whip James Clyburn recently said if the surge were successful, it would be "a real problem for us" — a revised set of talking points is being worked up by Democrats that declares the escalation of troops in Iraq has not been successful despite White House claims otherwise.

That point is expected to be sharpened on Thursday after lawmakers receive the latest National Intelligence Estimate ahead of the report due next month. Democrats are likely to emphasize the potential threats listed in the NIE as demonstrative of the Iraqi government's failure to achieve political reconciliation.

One leadership aide previewed the new argument — laid out in an hour-long conference call Tuesday — by saying that limited military success does not mean the surge has fulfilled its goals. The contention is that the surge was implemented to give an opportunity for the political process to get moving and "obviously" that hasn't happened.

Meanwhile, the White House is trying to set the stage for justifying a continued U.S. military surge in Iraq. Gen. David Petraeus, the head of Multinational Forces in Iraq, and Ambassador Ryan Crocker are set to deliver a report in the second week of September that will show the military surge has reduced the level of violence.

Ahead of the congressionally mandated testimony, Crocker said Tuesday that even if the political benchmarks have not been met, that does not mean Iraq has reached "the definitive failure of the state or the society."

"Conversely, to make them all would not by any means mean that they've turned the corner and it's a sun-dappled upland from here on in with peace and harmony and background music. It's just a lot more complex than that," he added.

President Bush warned Wednesday that a hasty withdrawal from the country would result in violence similar to the "killing fields" in southeast Asia after the U.S. pulled out of Vietnam.

"One unmistakable legacy of Vietnam is that the price of America's withdrawal was paid by millions of innocent citizens whose agonies would add to our vocabulary new terms like 'boat people,' 're-education camps' and 'killing fields,'" Bush told the Veterans of Foreign Wars convention in Kansas City, Mo.

"Some can argue our withdrawal from Vietnam carried no price for American credibility. But the terrorists see it differently," Bush added. "Unlike in Vietnam, if we were to withdraw before the job was done, this enemy would follow us home."

Roundly criticized for the Vietnam comparison — a rhetorical device previously avoided by the White House — anti-war Democrats lambasted the president, who they say took the wrong lesson from that war.

They also contended he is in the same denial that led earlier U.S. administrations to leave troops in Vietnam long after the country had been lost to communism.

"The surge was designed to give the Iraqi government time to take steps to ensure a political solution to the situation," 2008 White House hopeful Sen. Hillary Clinton said. "It has failed to do so. The White House's report in September won't change that. It is abundantly clear that there is no military solution to the sectarian fighting in Iraq. We need to stop refereeing the war, and start getting out now."

In a statement, House Speaker Nancy Pelosi said: "In an attempt to justify his stay-the-course strategy in Iraq, President Bush is offering false lessons from history. The American people have already judged the president's war in Iraq as the wrong war at the wrong time, and are ready for our troops to come home," she said.

"Whatever improvements in security that may have resulted from the efforts of our troops since the surge began, Iraqi leaders have not done the hard political work on which the future of their country depends. And therefore, the purpose of the surge — to enable the Iraqis to produce political reconciliation — has not been accomplished," she said.

Sen. Carl Levin, D-Mich., was among the first to invoke the adopted Democratic approach when on Monday he described the government of Iraqi Prime Minister Nouri al-Maliki as "non-functional."

On Wednesday after the president's speech, retired Brig. Gen. John Johns, a Vietnam veteran speaking for Democratic war opponents, said no matter what success the U.S. has, Iraq is lost.

"We keep blaming the politicians in Iraq for not doing their job. We gave them a situation — mission impossible. There is no way, there is no way that a government is going to pull humpty dumpty back together again," he said.

"This frustration could become an exit strategy by default," Carlos Pascual, director of foreign policy studies at the Brookings Institution study center in Washington, D.C., told The Associated Press. "It's 'the Iraqis didn't hold up their end of the bargain and so it's time to leave.'"

Al-Maliki's response to the new line of criticism offers no comfort to the White House, which tried to prop up the prime minister during the president's VFW speech. Prior to the speech, al-Maliki said he would "pay no attention" to his American critics and if necessary "find friends elsewhere." He was in Syria at the time of his statement.

In the U.S., Republican lawmakers are also being pressured — to continue their support for Bush's strategy. Freedom's Watch, a new group whose leadership includes former Bush spokesman Ari Fleischer, has launched a five-week, $15 million ad campaign targeting Republicans who have softened their support for the war.

Anti-war group Americans United for Change described the campaign as an effort to "swift boat" dovish GOP lawmakers — such as Sen. Pete Domenici and Rep. Walter Jones — calling it the same tactic used in 2004 to raise doubt about then-presidential candidate Sen. John Kerry's valor in Vietnam.

FOX News' Trish Turner and Molly Hooper contributed to this report.