In a July 2005 letter, Osama Bin Laden's top deputy outlined al Qaeda's vision for transforming the Middle East into a terrorist sanctuary. The first step in their master plan is to "expel the Americans from Iraq." Next, al Qaeda envisions filling "the void stemming from the departure of the Americans" by taking control of Sunni areas in Iraq. A violent "jihad wave" could then begin spreading throughout the region.

Al Qaeda knows they cannot "expel" Americans by defeating our military. Instead, their strategy is to weaken our morale and convince us to give up. They use barbaric tactics against innocent civilians to ignite sectarian violence among Iraqis. They explode bombs with chlorine gas to suffocate and kill. They send young children on suicide bombing missions. And they won't relent unless stopped by force.

As al Qaeda's war rages on, Congress has passed legislation that would require U.S. troops to begin leaving Iraq by this October. It would also establish a goal of removing most U.S. troops by the end of March 2008. I opposed this measure, and the President has vetoed it. I believe our nation's focus must be on success, not on leaving Iraq as soon as possible. I also believe our nation's generals are more qualified than members of Congress to make strategic judgments about the deployment of U.S. troops. Congress should fund our troops without micromanaging their commanders.

Additionally, while the legislation would allow "targeted" strikes against al Qaeda, far too few U.S. troops would remain to keep al Qaeda from gaining control of Iraq's Sunni regions. That is why Senator Joe Lieberman, the 2000 Democratic Vice Presidential nominee, recently proclaimed, "When politicians declare that Iraq is 'lost' in reaction to al Qaeda's terrorist attacks and demand timetables for withdrawal, they are doing exactly what al Qaeda hopes they will do."

Like all Americans, I want our men and women home as soon as possible. But we have a responsibility -- to our soldiers in the field, to future generations of Americans, and perhaps most importantly, to the families of the injured and fallen -- to give the new security plan a chance to succeed. Already, we are seeing encouraging signs. Sectarian violence is down by one-third. In the Anbar province, Sunni tribes are increasingly fighting al Qaeda terrorists. Predictably, however, al Qaeda has unleashed deadly attacks to counter our progress. No one expected peace overnight. General Petraeus has said success will take more time and sacrifice.

As General Petraeus recently stated, "Iraq is the central front of al Qaeda's global campaign." Al Qaeda certainly sees it as such. While they are not the only enemy in Iraq, the General describes them as "probably public enemy number one." We cannot leave Iraq's future in their hands. Doing so would bring al Qaeda a big step closer to fulfilling their vision of Middle East terror. That would threaten our national security and put Americans at heightened risk. Success in Iraq must be our only option.