Treaty of Tripoli
The Treaty of Tripoli was a treaty between the United States during the administration of George Washington and various Barbary states of north Africa, ratified in early 1797. The actual background of this treaty - piracy of American vessels and general acrimony between the states - is rather unimportant to modern Americans. However, an important clause in the treaty provides a clear, public statement that the American founders did not see the United States as a Christian nation, a common claim made by conservatives, evangelicals, and Dominionists today.
 Text of the treaty
"Article 1. There is a firm and perpetual peace and friendship between the United States of America and the Bey and subjects of Tripoli, of Barbary, made by the free consent of both parties, and guarantied by the most potent Dey and Regency of Algiers.
Art. 2. If any goods belonging to any nation with which either of the parties is at war, shall be loaded on board of vessels belonging to the other party, they shall pass free, and no attempt shall be made to take or detain them.
Art. 3. If any citizens , subjects, or effects, belonging to either party, shall be found on board a prize vessel taken from an enemy by the other party, such citizens or subjects shall be set at liberty, and the effects restored to the owners.
Art. 4. Proper passports are to be given to all vessels of both parties, by which they are to be known. And considering the distance between the two countries, eighteen months from the date of this treaty, shall be allowed for procuring such passports. During this interval the other papers, belonging to such vessels, shall be sufficient for their protection.
Art. 5. A citizen or subject of either party having bought a prize vessel, condemned by the other party, or by any other nation, the certificates of condemnation and bill of sale shall be a sufficient passport for such vessel for one year; this being a reasonable time for her to procure a proper passport.
Art. 6. Vessels of either party, putting into the ports of the other, and having need of provisions or other supplies, they shall be furnished at the market price. And if any such vessel shall so put in, from a disaster at sea, and have occasion to repair, she shall be at liberty to land and re-embark her cargo without paying any duties. But in case shall she be compelled to the land her cargo.
Art. 7. Should a vessel of either party be cast on the shore of the other, all proper assistance shall be given to her and her people; no pillage shall be allowed; the property shall remain at the disposition of the owners; and the crew protectedand succored till they can be sent to their country.
Art. 8. If a vessel of either party should be attacked by an enemy, within gun-shot of the forts of the other , she shall be defended as much as possible. If she be in port she shall not be seized on or attacked, when it is in the power of the other party to protect her. And when she proceeds to sea, no enemy shall be allowed to pursue her from the same port, within twenty-four hours after her departure.
Art. 9. The commerce between the United States and Tripoli; the protection to be given to merchants, masters of vessels, and seamen; the reciprocal right of the establishing Consuls in each country; and the privileges, immunities, and jurisdiction, to be on the same footing with those of the most favored nations respectively.
Art. 10. The money and presents demanded by the Bey of Tripoli, as a full and satisfactory consideration on his part, and on the part of his subjects, for this treaty of perpetual peace and friendship, are acknowledged to have been received by him previous to his signing the same, according to a receipt which is hereto annexed, except such as part as is promised, on the part of the United States, to be delivered and paid by them on the arrival of their Consul in Tripoli; of which part a note is likewise hereto annexed. And no pretense of any periodical tribute of further payments is ever to be made by either party.
Art. 11. As the Government of the United States of America is not, in any sense, founded on the Christian religion; as it has in itself no character of enmity against the laws, religion, or tranquillity, of Mussulmen; and, as the said States never entered into any war, or act of hostility against any Mahometan nation, it is declared by the parties, that no pretext arising from religious opinions, shall ever produce an interruption of the harmony existing between the two countries.
Art. 12. In case of any dispute, arising from a violation of any of the articles of this treaty, no appeal shall be made to arms; nor shall war be declared on any pretext whatever. But if the Consul, residing at the place where the dispute shall happen, shall not be able to settle the same, an amicable referrence shall be made to the mutual friend of the parties, the Dey of Algiers; the parties hereby engaging to abide by his decision. And he, by virtue of his signature to this treaty, engages for himself and successors to declare the justice of the case, according to the true interpretation of the treaty, and to use all the means in his power to enforce the observance of the same."
As the bolded section of Article 11 states is not, in any sense founded on Christian thought or practice, this provides a key support to the idea that the Constitution was godless. While several Founders did in private correspondence make statements similar to what is said in the Treaty, this was a clarification that was placed in law, and approved by a vote in the Senate. It may be useful to point this out to fundies who refuse to back down from the "Christian Nation" argument.