I recently had my last name changed. I had to go to a court hearing for that and before it began, the judge told me that I had to swear to tell the truth ‘so help me God.’ Even though it went against my own beliefs and thus didn’t mean anything to me so far as guaranteeing my truthfulness, I said it anyway. I was afraid that the judge might retaliate against me if I asked to swear another way and refuse to grant my name change. I also wasn’t sure of the legality of the whole thing. The experience left me feeling awful, like I’d sold myself out.
In the UK, it is ok to take an oath to tell the truth with no reference to any religious books. Perhaps if you enquired of the courts or legal advisors whether it is possible to do so in the US? It could help you to conduct yourself in court while feeling congruent should you find yourself so unfortunate as to appear in court again.
Honestly, I don't know why this practice hasn't been fought in the courts. Perhaps most people consider it too trivial to bother with, but it's clearly a violation of the establishment clause, and it causes discomfort and even fear of retaliation if someone even mentions it to whatever official is involved. Where has the ACLU been on this?
I know this. My objection is that swearing an oath to God as the de facto practice instead of a secular affirmation constitutes an establishment of religion. The option for the swearee is actually irrelevant to the constitutional issue.
I know this discomfort and fear, having been through it. I chose to voice my opposition to a religious oath, but only because I had a lawyer with me, who spoke to the judge about it beforehand. Had I not had a lawyer, I would have been too afraid to say anything.
As long as you can justify why you said it-its okay.