“”John Adams recognized that America is not founded on any particular religion. But that it was founded in a system of ideas that finds its root in God, as Christians understand Him, was perfectly obvious to him, and to the people of his time.””
Adams and the founders compromised Christianity in lieu of a system of pluralism and did not really understand what TRUE liberty really meant,thus the US is failing in a mere 234 years.
Pope Leo XIII understood true and false liberty
Excerpt from Libertas
http://www.vatican.va/holy_father/leo_xiii/encyclicals/documents/hf_l-xiii_enc_20061888_libertas_en.html
5. Liberty, then, as We have said, belongs only to those who have the gift of reason or intelligence. Considered as to its nature, it is the faculty of choosing means fitted for the end proposed, for he is master of his actions who can choose one thing out of many. Now, since everything chosen as a means is viewed as good or useful, and since good, as such, is the proper object of our desire, it follows that freedom of choice is a property of the will, or, rather, is identical with the will in so far as it has in its action the faculty of choice. But the will cannot proceed to act until it is enlightened by the knowledge possessed by the intellect. In other words, the good wished by the will is necessarily good in so far as it is known by the intellect; and this the more, because in all voluntary acts choice is subsequent to a judgment upon the truth of the good presented, declaring to which good preference should be given. No sensible man can doubt that judgment is an act of reason, not of the will. The end, or object, both of the rational will and of its liberty is that good only which is in conformity with reason.
6. Since, however, both these faculties are imperfect, it is possible, as is often seen, that the reason should propose something which is not really good, but which has the appearance of good, and that the will should choose accordingly. For, as the possibility of error, and actual error, are defects of the mind and attest its imperfection, so the pursuit of what has a false appearance of good, though a proof of our freedom, just as a disease is a proof of our vitality, implies defect in human liberty. The will also, simply because of its dependence on the reason, no sooner desires anything contrary thereto than it abuses its freedom of choice and corrupts its very essence. Thus it is that the infinitely perfect God, although supremely free, because of the supremacy of His intellect and of His essential goodness, nevertheless cannot choose evil; neither can the angels and saints, who enjoy the beatific vision. St. Augustine and others urged most admirably against the Pelagians that, if the possibility of deflection from good belonged to the essence or perfection of liberty, then God, Jesus Christ, and the angels and saints, who have not this power, would have no liberty at all, or would have less liberty than man has in his state of pilgrimage and imperfection. This subject is often discussed by the Angelic Doctor in his demonstration that the possibility of sinning is not freedom, but slavery. It will suffice to quote his subtle commentary on the words of our Lord: “Whosoever committeth sin is the slave of sin.”(3) “Everything,” he says, “is that which belongs to it a naturally. When, therefore, it acts through a power outside itself, it does not act of itself, but through another, that is, as a slave. But man is by nature rational. When, therefore, he acts according to reason, he acts of himself and according to his free will; and this is liberty. Whereas, when he sins, he acts in opposition to reason, is moved by another, and is the victim of foreign misapprehensions. Therefore, `Whosoever committeth sin is the slave of sin.’ “(4) Even the heathen philosophers clearly recognized this truth, especially they who held that the wise man alone is free; and by the term “wise man” was meant, as is well known, the man trained to live in accordance with his nature, that is, in justice and virtues
What naturalists or rationalists aim at in philosophy, that the supporters of liberalism, carrying out the principles laid down by naturalism, are attempting in the domain of morality and politics. The fundamental doctrine of rationalism is the supremacy of the human reason, which, refusing due submission to the divine and eternal reason, proclaims its own independence, and constitutes itself the supreme principle and source and judge of truth. Hence, these followers of liberalism deny the existence of any divine authority to which obedience is due, and proclaim that every man is the law to himself; from which arises that ethical system which they style independent morality, and which, under the guise of liberty, exonerates man from any obedience to the commands of God, and substitutes a boundless license. The end of all this it is not difficult to foresee, especially when society is in question. For, when once man is firmly persuaded that he is subject to no one, it follows that the efficient cause of the unity of civil society is not to be sought in any principle external to man, or superior to him, but simply in the free will of individuals; that the authority in the State comes from the people only; and that, just as every man’s individual reason is his only rule of life, so the collective reason of the community should be the supreme guide in the management of all public affairs. Hence the doctrine of the supremacy of the greater number, and that all right and all duty reside in the majority. But, from what has been said, it is clear that all this is in contradiction to reason. To refuse any bond of union between man and civil society, on the one hand, and God the Creator and consequently the supreme Law-giver, on the other, is plainly repugnant to the nature, not only of man, but of all created things; for, of necessity, all effects must in some proper way be connected with their cause; and it belongs to the perfection of every nature to contain itself within that sphere and grade which the order of nature has assigned to it, namely, that the lower should be subject and obedient to the higher.
16. Moreover, besides this, a doctrine of such character is most hurtful both to individuals and to the State. For, once ascribe to human reason the only authority to decide what is true and what is good, and the real distinction between good and evil is destroyed; honor and dishonor differ not in their nature, but in the opinion and judgment of each one; pleasure is the measure of what is lawful; and, given a code of morality which can have little or no power to restrain or quiet the unruly propensities of man, a way is naturally opened to universal corruption. With reference also to public affairs: authority is severed from the true and natural principle whence it derives all its efficacy for the common good; and the law determining what it is right to do and avoid doing is at the mercy of a majority. Now, this is simply a road leading straight to tyranny. The empire of God over man and civil society once repudiated, it follows that religion, as a public institution, can have no claim to exist, and that everything that belongs to religion will be treated with complete indifference. Furthermore, with ambitious designs on sovereignty, tumult and sedition will be common amongst the people; and when duty and conscience cease to appeal to them, there will be nothing to hold them back but force, which of itself alone is powerless to keep their covetousness in check. Of this we have almost daily evidence in the conflict with socialists and members of other seditious societies, who labor unceasingly to bring about revolution. It is for those, then, who are capable of forming a just estimate of things to decide whether such doctrines promote that true liberty which alone is worthy of man, or rather, pervert and destroy it.
Don't throw out the baby with the bath water. Adams and the founders didn't do anything to Christianity. They created a system of government. Period.
In creating that system of government I respectfully submit that Adams and the founders did recognize and understand the TRUE source and nature of liberty. Adams wrote that the "Constitution was made only for a religious and moral people", and with the founders, religion was identified with Christianity. When Samuel Adams signed the Declaration he declared, “We have this day restored the Sovereign to Whom all men ought to be obedient. He reigns in heaven and from the rising to the setting of the sun, let His kingdom come.”
From your quotation of Pope Leo XIII :...St. Augustine and others urged most admirably against the Pelagians that, if the possibility of deflection from good belonged to the essence or perfection of liberty, then God, Jesus Christ, and the angels and saints, who have not this power, would have no liberty at all, or would have less liberty than man has in his state of pilgrimage and imperfection. This subject is often discussed by the Angelic Doctor in his demonstration that the possibility of sinning is not freedom, but slavery. It will suffice to quote his subtle commentary on the words of our Lord: “Whosoever committeth sin is the slave of sin.”(3) “Everything,” he says, “is that which belongs to it a naturally. When, therefore, it acts through a power outside itself, it does not act of itself, but through another, that is, as a slave. But man is by nature rational. When, therefore, he acts according to reason, he acts of himself and according to his free will; and this is liberty. Whereas, when he sins, he acts in opposition to reason, is moved by another, and is the victim of foreign misapprehensions. Therefore, `Whosoever committeth sin is the slave of sin.’ “(4) Even the heathen philosophers clearly recognized this truth, especially they who held that the wise man alone is free; and by the term “wise man” was meant, as is well known, the man trained to live in accordance with his nature, that is, in justice and virtues...
[emphasis mine]
Is it the unregenerate man's nature to live in accordance with justice and virtues?
But a natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised.
1 Corinthians 2:14
Jesus did say, "Whoever commits sin is the slave of sin", but he also said, "If the Son makes you free, you shall be free indeed. Scripture also says this about freedom and slavery:
17But thanks be to God that though you were slaves of sin, you became obedient from the heart to that form of teaching to which you were committed,
18and having been freed from sin, you became slaves of righteousness.
19I am speaking in human terms because of the weakness of your flesh For just as you presented your members as slaves to impurity and to lawlessness, resulting in further lawlessness, so now present your members as slaves to righteousness, resulting in sanctification.
20For when you were slaves of sin, you were free in regard to righteousness.
21Therefore what benefit were you then deriving from the things of which you are now ashamed? For the outcome of those things is death.
22But now having been freed from sin and enslaved to God, you derive your benefit, resulting in sanctification, and the outcome, eternal life.
Romans 6:17-22
I think the founders would have agreed with Pope Leo XIII's assessment in Section 16 that you cite, but they also recognized the limitations and dangers of human government, and puts checks on it. James Madison's "If men were angels...", quote demonstrates that they recognized the sinful nature of man, and because of that nature they strove to fashion a system of self-government under God. Self government to prevent the government from obtaining to much power and acting outside the scope of its authority, as well as to enjoy the blessings of liberty. Speaking of liberty in terms of "blessings" would have made no sense unless they understood the nature of the source of those blessings.
Cordially,