Ubi Arcano Dei Consilio §46

⁴⁶ There exists an institution able to safeguard the sanctity of the law of nations. This institution is a part of every nation; at the same time it is above all nations. She enjoys, too, the highest authority, the fullness of the teaching power of the Apostles. Such an institution is the Church of Christ. She alone is adapted to do this great work, for she is not only divinely commissioned to lead mankind, but moreover, because of her very make-up and the constitution which she possesses, by reason of her age-old traditions and her great prestige, which has not been lessened but has been greatly increased since the close of the War, cannot but succeed in such a venture where others assuredly will fail.