I suppose it all depends on Ponnuru’s definition of "ability." If by "ability" he means "capacity," then I believe he is mistaken about the meaning of the Declaration of Independence and hence wrong to carp on Brooks. (Here Ponnuru’s ellipsis, which omits Brooks’s reference to God’s creating men with "the right to liberty," is telling; it suggests he does not want to examine the foundation of legitimate government.) A capacity for some action can be natural but latent, as in the potential of a child to rule himself IF properly habituated and instructed (or so I understand Aristotle’s teaching in his Nicomachean Ethics).

But if "ability" refers not to a natural capacity that can develop from a potential to an actuality but rather the actuality itself, then he makes a plausible case for criticizing Brooks’s assumption that Iraqis are willing and able to govern themselves. I like Peter’s formulation, though: "close enough for a column."

"The Capacity of Mankind to Govern Itself"

There is sufficient ambiguity in Brooks’s disputed phrase for reasonable people to disagree over it. And the issue is important enough in the current circumstances that it is worth trying to clarify the position. Allow me to quote myself (from an old article) to try to do so.
Democracy requires more of its citizens than any other form of government. It depends on the capacity of the citizens to govern themselves. But the habits and dispositions of self government are difficult to acquire and to sustain. They are rooted in moral and political principles in which each new generation must be educated. It is no accident that history provides so few examples of successful and enduring democracies. In the American democracy today, we have largely lost sight of those moral and political principles (in which the Iraqis have largely yet to be educated) which provide the common ground of American political community and inform the civic character required of American citizens.
We Hold These Truths
America began with a ringing affirmation of a fundamental moral and political truth: “We hold these truths to be self evident, that all men are created equal, that they are endowed by their creator with certain inalienable rights.” The truth of human equality and liberty was asserted against all despotisms of race, class, or religion.
That men throughout most of history (and throughout most of the world still today) tyrannized one another in an infinite variety of ways was not proof (to the American founders) that human beings do not possess equal rights by nature—rather it was proof of how rare and difficult a thing it is to secure them. It is proof of the philosophic rigor, the high moral discipline, the rare political sagacity, and—one must add—the great good fortune that is required for reflection and free choice to prevail over ignorance, prejudice, accident, and force.
Proclaiming that all men everywhere and at all times possess by nature equal rights to life, liberty, and the pursuit of happiness, the American founders undertook the historic effort to secure these rights, so far as they thought they could then be secured, to a small people at a particular place and time. They were acutely conscious of the limits of their ability to secure these rights. When they were able to establish a “more perfect union” they understood full well how far from perfection they remained. It was all the new republic could do in the first century of its existence to keep the experiment in freedom from failing miserably at home as the principles espoused in the American revolution slowly and uncertainly began to take hold on the minds if not yet in the politics of other peoples in the world.
In the course of its history, the American people have many times fallen beneath the high standards they set for themselves at the beginning. They have strayed from those principles, and they have forgotten them, and become confused about them, and allowed misunderstood self-interest to obscure them. The reason that Abraham Lincoln is rightly regarded as the greatest democratic statesman is that he kept America from abandoning those principles as the foundation of American democracy. His statesmanship preserved for future generations of Americans the moral truth of human equality as the pole star of their political life: as “a standard maxim for free society, which should be familiar to all, and revered by all; constantly looked to, constantly labored for, and even though never perfectly attained, constantly approximated, and thereby constantly spreading and deepening its influence, and augmenting the happiness and value of life to all people of all colors everywhere.”
The “genius” of the American people at the time of the American revolution and founding made it both possible and necessary to establish a regime based on the republican principles proclaimed in the Declaration of Independence. As Jefferson said in explaining the genesis of the Declaration of Independence, the ideas expressed in it were “the common sense of the subject” in America. He was merely expressing “the American mind.” It was only because the American people had learned to embrace republican principles that it was possible to establish an American republic. The founders were animated by “that honorable determination which animates every votary of freedom to rest all our political experiments on the capacity of mankind for self-government.” But they understood that this was a capacity that Americans would have to demonstrate for themselves, and continue to demonstrate each generation. As the Declaration proclaims, the just powers of government are derived from "the consent of the governed." Only a people prepared to consent to a republic are capable of establishing one. This means a people prepared to recognize their own humanity and that of their fellow citizens; who will neither aspire to be masters nor submit to be slaves; who are prepared to rule and be ruled in turn; who are prepared to abide by the laws they claim the right to make for themselves. A people that means to be free must have the virtues necessary to sustain their freedom. Do we? Do the Iraqis?

Brooks’s reference to God’s creating men with "the right to liberty," is telling;

And so was this exchange of

Peter Schramm: Dinesh D’Souza thinks that the West became rich because it introduced three new things: science, democracy, and capitalism.

Marc Lamb: With all due respect for Dinesh D’Souza, and what he thinks, and all wonders of "science, democracy, and capitalism." But, this is just plain hogwash. The man gets the cart waaaay before the horse.
America, and "West became rich" simply because God has deemed it so. That and one very, very important lesson we have come to cherish: Above all things, America values, in James Madison’s immortal words, "liberty of conscience."

John Moser: Excuse me if this comes across as blasphemous, but is Mr. Lamb really claiming that "because God has deemed it so" is a sufficient explanation for anything?

Methinks this notion of "God" in the "affairs of men," as Franklin put it, needs some serious re-consideration in American conservative thought today. I mean, for our souls sake. :)

I have to agree with Ramesh on this one. The Declaration absolutely does not state that God has endowed "all human beings with . . . the ability to function as democratic citizens."

In fact most of the Declaration is a list of the ways in which the colonists were treated undemocratically by a monarchy in England, who were themselves certainly unable to function as Democratic citizens. We had to shoot them to make them function that way.