Claiming the United States is a Christian nation is one of the most un-American things one could say. America was founded on separation of church & state. It doesn't matter if 51% of America is Christian or 99%, religion should remain out of the government. Requiring people to swear on the Bible before testifying is an utterly tribal-like notion that has no place in the United States.
This process has outlived its welcome, it should no longer be a part of the court system. It's a cultural thing at this point and the rationale for doing it is that's just what you do, which is a really foolish way to go about this or anything else on the planet.
One of our founding principles is freedom of religion, which is the freedom to choose to believe in anything or nothing. While it is important to have each person testifying in court swear (using some words that they find binding) that they will tell the truth, to many Americans the Bible itself is not true, and thus is hardly a good authority for binding them to truth.
Yes, our government should not be smudged by acting on persons religious beliefs. Not all people believe in God, let alone in the Bible. It is an outdated custom which expects conformity to Christianity. For those of other religions or who are agnostic, swearing on the Bible is a joke. If it means nothing to the individual why would he follow through with his promise?
When this country was founded one of the principles that was mentioned in a letter from Thomas Jefferson was that of separation of church and state. This was to protect our government from the rule of church institutions like the Catholic Church or the Church of England. I'd say that that was accomplished. It was never intended to mean that you couldn't say a prayer in a government setting or swear on a bible. To answer a question on a dissenting viewpoint, I would have no problem swearing on a Quran if I was in testifying in a court in a Middle Eastern country.
I think you guys are misreading the question. It's not necessarily right to swear on the bible, but that doesn't mean its wrong. Its just a ritual, like Lebron James doing some warm up shots. Do you think it makes a difference? This suggests its an issue, which its not.