For years, extreme right-wing groups exacerbated divisions in Congress by applying political pressure to the Republican majority. Now that Democrats are in control, the extreme left is flexing its muscle. If this keeps Congress from a realistic approach to the war in Iraq, the results could be devastating.

As a case in point, the left-wing Web site MoveOn.org had the audacity this week to refer in an ad to Gen. David Petraeus as "General Betray Us" and to say he would "cook the books" in his report to Congress in order to favor the Bush administration's line. That's the sort of personal attack that diminishes serious debate as it sullies the reputation of a man who has served his country with honor.

Contrary to this, Petraeus and Ambassador Ryan Crocker have been sincere and honest in their assessments of the situation in Iraq. The overall tone of their testimony has been a reinforcement of something the American people need to understand. There are no quick fixes, no easy ways to help the Iraqis overcome their own divisions and establish independent self-rule. That effort will need time and a huge continued investment of human and financial resources.

But to pull out now would result in a chaos and struggle that "will mean massive human suffering — well beyond what has already occurred within Iraq's border," Crocker said.

Those two realities must be the foundation for any future Iraq policy. Extremists tend to discount these and focus solely on the mistakes that led the United States to this point, which is counterproductive.

Fortunately, some on both sides of the aisle in Congress seem interested in real debate. Compromises are possible. Some Democrats, however, are feeling pressure from the extreme left to vote to cut funding for the war in order to force greater troop withdrawals.

If anything, resources need to be realigned to focus on new al-Qaida strongholds in Pakistan and Afghanistan. But Iraq should not be abandoned.

Extremists have played a role in American politics from the beginning, but this nation's leaders generally have been pushed toward the center by realities. We doubt that a Democratic president would support an irresponsible withdrawal simply because that president wouldn't want to be saddled with the blame for what would result.

It would help, however, if leaders from both major political parties would condemn extremist elements who are coarsening the national debate.