If the Bush domino theory about the Middle East is correct, then building a democratic, prosperous Iraq will do far more to push Syria into changing its terrorist ways than merely invading it.
Of course, the American-led ouster of Saddam Hussein in just three weeks has no doubt also helped focus the thinking of Syria's Baath Party leaders about not repeating their "unfriendly" actions toward US interests anytime soon.
But for now, persuasion by example will be a a much better force for good than, well, brute force. As convenient as it may be just to turn the US Army's Third Division to the west and into Syria, the US needs to remember that Damascus did vote for Resolution 1441 last fall at the United Nations and has helped capture top Al Qaeda operatives for the US.
It has also taken steps toward negotiating with Israel for the return of the Golan Heights (which it lost in the 1967 war). And there's still hope that its British-trained young leader, Bashar al-Assad, won't be as ruthless, backward, or conniving as the regime of his late father, Hafez al-Assad.
All that adds up to a preference for administering tough diplomacy to Syria right now, as the Bush administration has done with its barbed warnings toward Damascus.
If Mr. Hussein and any of his top people have been given haven in Syria, they must be turned over to the Iraq Interim Authority as soon as it is formed. (That's more palatable than handing them over to the Americans.)
And if Arab suicide bombers are entering Iraq through Syria to strike at US forces, then Damascus must realize it is a party to an act of war.
The other US complaints about Syria have been around awhile: that it harbors Palestinian terrorists and supports Hezbollah attacks on Israel from Lebanon; that it has chemical weapons; and that its troops shouldn't be in Lebanon.
Of those, the most serious is the possession of chemical weapons. And the best way to get rid of those is to convene Middle East talks to discuss eventually ridding the region of all weapons of mass destruction - including Israel's nuclear weapons and Iran's nuclear-weapons program.
Syria may hang tough with the US on these complaints for a while, hoping it can gain leverage to win back the Golan Heights from Israel. If so, the US can help on that point, and win a diplomatic victory with Syria rather than a war against it.