Peggy Noonan offers a fine column in today's OpinionJournal.com.
We cannot leave Iraq and should not leave Iraq. Certainly lately, since the transfer of sovereignty, things seem to be looking up, but that may well prove temporary. But the great reason, as I have written before on Iraq, is that there's no way 'round it but through it. We have to stay, and we have to win. I define winning as the yielding up of, at the least, a relatively stable society unafflicted by governmental sadism and dictatorship, and, at the most, a stable society in a fledgling democracy that demonstrates, with time, that the forces of Arab moderation, tolerance and peacefulness can triumph. Such an outcome would give so much good to the world. What a brilliant beacon this Iraq could be, and what a setback to terrorists, who thrive in darkness.
And this, best of all:
...We have a national-security obligation to foster democracy in the world because democracy tends to be the most peaceful form of government. Democracies tend to be slower than dictatorships to take up arms, to cross borders and attempt to subdue neighbors, to fight wars. They are on balance less likely to wreak violence upon the world because democracies are composed of voters many of whom are parents, especially mothers, who do not wish to see their sons go to war. Democracy is not only idealistic, it is practical.
Ms. Noonan couldn't be more right.