Commentators have noted parallels between President Bush's second inaugural address and President Kennedy's 1961 inaugural; one witty historian suggested that it was "the best speech Woodrow Wilson ever wrote." What struck me, however, was the remarkable similarity between the president's second inaugural and Pope John Paul II's second address to the United Nations.

Here is the pope in 1995:

"We are witnessing an extraordinary global acceleration of that quest for freedom which is one of the great dynamics of human history. This phenomenon is not limited to any one part of the world; nor is it the expression of any single culture...[Its] global character...confirms that there are indeed universal human rights, rooted in the nature of the person...

"...we do not live in an irrational or meaningless world. On the contrary, there is a moral logic which is built into human life and which makes possible dialogue between individuals and peoples....[thus] it is possible for mankind's historical journey to follow a path which is true to the finest aspirations of the human spirit.

"We have within us the capacities for wisdom and virtue. With these gifts, and with the help of God's grace, we can build...a civilization worthy of the human person, a true culture of freedom...And in doing so, we shall see that the tears of this century have prepared the ground for a new springtime of the human spirit."

And here is the president in 2005:

"The best hope for peace in our world is the expansion of freedom in all the world...Eventually, the call of freedom comes to every mind and every soul. We do not accept the existence of permanent tyranny because we do not accept the possibility of permanent slavery...

"We go forward with complete confidence in the eventual triumph of freedom. Not because history runs on the wheels of inevitability...[but] because freedom is the permanent hope of mankind, the hunger in dark places, the longing of the soul...History has an ebb and flow of justice, but history also has a visible direction, set by liberty and the Author of Liberty...

"Renewed in our strength --- tested, but not weary --- we are ready for the greatest achievements in the history of freedom."

There are some very large ideas in play here, and it's worth teasing them out, briefly:

1. There is a universal human nature. However different human beings are, there is, at bottom, a common humanity composed of common characteristics, longings, aspirations and temptations.

2. There is a universal moral law inscribed in this common human nature, a moral law we can know by reflecting on those common human experiences.

3. This universal moral law teaches us the dignity of the human person, from which we can deduce certain political truths: basic human rights are inalienable; government exists to protect and advance those rights; rights imply responsibilities.

4. That moral law and those political truths set a horizon of achievement in history. The defense of freedom is a moral obligation, not simply an exercise in self-interest. The goal of advancing freedom's cause throughout the world is not a romantic pipedream but a moral imperative built into the human condition --- by, biblical people will insist, God himself.

Much ink has been spilled over the differences between the Bush administration and the Holy See on the prudence of invading Iraq to depose Saddam Hussein. Some have wondered how the administration and the Vatican could work together in the future. Here is one part of the answer: because the world's leading political power and the world's leading moral authority are both committed to the defense and advance of freedom in the world, over against those so-called "realists" who insist that "stability" is the goal in world politics.

Even given that common commitment, there will be disagreements over the prudence of this or that policy; that's inevitable. Still, that fact of life doesn't mitigate the importance of agreement on these four large ideas, which boldly challenge the conventional wisdom of the unrealistic realists in the name of a moral "logic" accessible to all.

George Weigel is a senior fellow of the Ethics and Public Policy Center in Washington, D.C.