One Bite From Benedict's Address

...the one at the White House.

...The preservation of freedom calls for the cultivation of virtue, self-discipline, sacrifice for the common good and a sense of responsibility towards the less fortunate. It also demands the courage to engage in civic life and to bring one’s deepest beliefs and values to reasoned public debate. In a word, freedom is ever new. It is a challenge held out to each generation, and it must constantly be won over for the cause of good (cf. Spe Salvi, 24). Few have understood this as clearly as the late Pope John Paul II. In reflecting on the spiritual victory of freedom over totalitarianism in his native Poland and in eastern Europe, he reminded us that history shows, time and again, that “in a world without truth, freedom loses its foundation”, and a democracy without values can lose its very soul (cf. Centesimus Annus, 46). Those prophetic words in some sense echo the conviction of President Washington, expressed in his Farewell Address, that religion and morality represent “indispensable supports” of political prosperity.

Only the truth can make you free.

And on the political science behind the Founding:

...What I find fascinating in the USA is that it began with a positive concept of secularism. Because this new people was made up of communities and persons who had escaped the State religions and wished to have a lay, secular State, which opens the doors to all confessions, to all forms of religious exercise. It was thus a willingly secular State, it was really contrary to a State Church, but secular truly for love of religion, of its authenticity, which can be lived only freely. And thus we find this fusion of a willingly and honestly secular State, but really for a religious will, to grant authenticity to religion. And we know that A.[lexis] de Tocqueville, studying America, saw that the secular institutions depend on a de facto moral consensus which exists among the citizens. This seems to me a fundamental and positive model to be considered also in Europe;...

That's likely the most positive Papal review of the Founding that's ever been issued.