"As the Government of the United States of America is not, in any sense, founded on the Christian religion [emphasis mine]; 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."
Of course, there are disagreements as to the significance and exact meaning of this passage. Naturally, most of those disagreements come from christians who fear their hegemony may be threatened. However, as with any contentious issue, it is valuable to study both sides of the argument.
Here is a little background regarding the treaty from Wikipedia:
At the time of the Treaty and for 300 years prior, the Mediterranean Sea lanes were largely controlled by the north African Muslim states of the Barbary Coast (Tripoli, Algiers, Morocco, and Tunis) through piracy. Hostages were either ransomed or sold into slavery. Over time, most countries found it expedient to simply pay a yearly tribute to the Barbary Sultans in exchange for safe passage through the Mediterranean. Following the American Revolution, the United States was no longer under the protection of the British tribute treaties, resulting in the crippling of U.S. commerce in the Mediterranean. Having no significant Navy, the U.S. decided to form tribute treaties with the Barbary states, such as this 1796 Treaty of Tripoli.
Perhaps you're saying to yourself: "The treaty clearly states that the U.S. was not founded on Christianity. The treaty was approved by the President and the Senate. What argument could possibly be brought to bear against these facts?" Well my friend, if you take away one thing from this post, make it this: The christian does not care about facts. On to the arguments raised, then.
One site, tektonics.org, seems to assert as its main argument that the section in question (Section 11) was left in because, at the time, the need for a workable treaty was so pressing that lawmakers did not feel that the "minutiae" of the treaty were important enough to delay approval of the document. This would be a reasonable assertion, if we were talking about, say, choosing between "sailors" and "seaman" to describe the hostages. However, article 11 is such an absolutely sweeping statement that it seems unreasonable to believe that this statement could be regarded as "minutiae." Granted, I don't know how politics were on a day-to-day basis in the 18th century, but could you imagine this happening? I'm having a hard time finding sources, but I think that it is reasonable to assume that in 1796, most of the free people in the United States considered themselves christian, most likely upwards of 90% of the population (I exclude slaves because I assume that lawmakers would not concern themselves over a slave's beliefs). For any politician, let alone the president and 32 senators*, to approve a document that categorically stated what article 11 does, it seems that they must have actually agreed with it. What's more, they must have known that their constituents agreed with it as well. Not ONE senator voted against the treaty. There is NO record of public outcry or complaint.
Tektonics also questions "Did Article 11 belong in the treaty at all?" This is beside the point. The fact is that the wording presented above was approved by the U.S. president, ratified by the senate, and apparently, implicitly at least, approved of by the American people.
Wallbuilders.com (quite an appropriate name for a christian group) argues the following:
Article XI simply distinguished America from those historical strains of European Christianity which held an inherent hatred of Muslims; it simply assured the Muslims that the United States was not a Christian nation like those of previous centuries (with whose practices the Muslims were very familiar) and thus would not undertake a religious holy war against them.
Maybe it's my fault. Maybe I'm reading the text of Article 11 too literally. Perhaps I have made the error, by assuming that a document that is centuries old can possibly have any meaning in the modern world when taken literally. I'm not crazy, am I? Article 11 does not say "Hey Muslims, don't worry. We're not the bad Christians. We're the goods ones. Love thy neighbor and all that," does it? No, it states, if I remember correctly, "... the Government of the United States of America is not, IN ANY SENSE, founded on the Christian religion..."
Wallbuilders also writes
It would also be absurd to suggest that President Adams (under whom the treaty was ratified in 1797) would have endorsed or assented to any provision which repudiated Christianity.
While, according to this site, the book Treaties and Other International Acts of the United States of America carries the text of the treaty, which, along with the signature of John Adams, contains the following clause:
Now be it known, That I John Adams, President of the United States of America, having seen and considered the said Treaty do, by and with the advice and consent of the Senate, accept, ratify, and confirm the same, and every clause and article thereof [emphasis mine]. And to the End that the said Treaty may be observed and performed with good Faith on the part of the United States, I have ordered the premises to be made public; And I do hereby enjoin and require all persons bearing office civil or military within the United States, and all others citizens or inhabitants thereof, faithfully to observe and fulfil the said Treaty and every clause and article thereof.
Those claiming that the United States is a christian nation, founded upon christian principles, are wrong. Unfortunately, this may prove irrelevant. Zealots in this country are pushing so hard for theocratic rule that it is perhaps only a matter of time until they take control. As with all despotic regimes, one of the first things they will do is alter the history books, erasing Article 11 and other documents that threaten their divine right to rule.
* According to Wikipedia, in November 1796 there were 16 states. Two senators each equals 32 senators.
Sources
http://en.wikipedia.org/wiki/Treaty_of_Tripoli
http://members.tripod.com/~candst/tnppage/tripoli.htm
http://www.tektonics.org/qt/tripoli.html
http://web.archive.org/web/20050308115648/http://www.stephenjaygould.org/ctrl/archive/boston_tripoli.html
http://www.wallbuilders.com/LIBissuesArticles.asp?id=125
http://www.sunnetworks.net/~ggarman/tripoli.html