McCain hasn't read the Constitution?

In an interview with Beliefnet, Arizona Sen. John McCain said that the U.S. Constitution establishes a Christian nation:

A recent poll found that 55 percent of Americans believe the U.S. Constitution establishes a Christian nation. What do you think?
I would probably have to say yes, that the Constitution established the United States of America as a Christian nation. But I say that in the broadest sense. The lady that holds her lamp beside the golden door doesn't say, “I only welcome Christians.” We welcome the poor, the tired, the huddled masses. But when they come here they know that they are in a nation founded on Christian principles.

Apparently he, like Rep. Ron Paul, missed the fact that the only reference to God in the U.S. Constitution is the reference to the "year of our Lord" in the date. The Constitutional Convention voted not to open with prayers, Article VI says that "no religious test shall ever be required as a qualification to any office or public trust under the United States," and the First Amendment says that "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof."

The Constitution establishes a democratic republic with a strong separation of church and state by comparison to other nations. The Bible, by contrast, speaks of theocratic political systems with rule by priests and kings.

In 1797, the Senate unanimously ratified and President John Adams signed the Treaty of Tripoli, Article 11 of which began with the words "As the Government of the United States of America is not, in any sense, founded on the Christian religion." (This treaty was quickly violated by Tripoli, and the renegotiated treaty of 1805 did not contain this article, but the important point is that this language was approved by the entire Senate and the President in 1797.)