Richard previously posted a blog entitled "Naked Unless Someone is Offended." This post I presume to claim be an extension of his thinking.
Ideally, in the US, no law can be enacted unless the public can prove a behavior can, has, or will harm another. The abortion debate is all about whether the fetus can be harmed or if the mother can be harmed - from both sides of the issue. Gay marriage, gerrymandering, minimum wage, voter-ID laws, deficit spending, foreign relations, income tax reforms, immigration reforms... its all about who is potentially harmed by the legislation produced by the majority. Gay marriage is a prime example of a majority harming the minority with bans and the courts ruling to restrict the power of the majority.
The majority of the public are not nudists - or at least not social nudists. Yet we have laws banning nudity as obscene. Obscene (as I noticed my spell check corrected to include the root "scene") has a history thus: http://www.etymonline.com/index.php?term=obscene
I also had to have Google define "prurient" for me: https://www.google.com/search?q=prurient&oq=prurient&aqs=chrome..69i57&sourceid=chrome&es_sm=93&ie=UTF-8#q=define+prurient
So I summarize that obscene is linked to "sexual" and if a "work" has no literary, artistic, political, or scientific value it can be deemed obscene. Being nude in public - or within view of the public, such as through the window of my home - has no literary value I can argue, nor artistic unless I stretch MY definition of art for those who have tattoos, piercings, or other modifications, nor scientific as my body is too normal to be medically relevant.
However, it is the political value that I zeroed in on. Denying my ability to dress as I please potentially harms me as it denies my Right to Free Speech and places restrictions on my activities or expression. Should my expression be intentionally sexual, then I could see the trier ruling against me - though that could be another conversation. However, almost every nudist I've met in person or on-line contends a non-sexual motivation for their clothes-free choices. So, as long as I claim non-prurient intentions and make no display "obviously" sexual then I have political value to my nudity. Any restriction goes against precedent mentioned on etymonline.com and I can claim harm.
The religious and parents also claim harm by viewing my nudity. They would have equal justification in the political realm. Sexualizing (as may happen without proper contextual explanation by the parents) children is illegal for obvious reasons - if not so obvious, I would be happy to provide instruction at another time. However, if simple nudity were akin to sexualizing children then a child witnessing their parent's nudity within the home would be equivalent to abuse and no nudist resort would be allowed to admit children.
Religious observance within an impartial state is enshrined in our very founding (ideally). To not provide some measure of shared observance the state loses it impartiality. However, many aspects of dogma are ignored by the state. Some people work the Sabbath as we are allowed to eat beef on Fridays and pork at any time we choose.
So again we are faced with quantifying harm. Is the majority viewing nudity harmed more than the minority banned from expressing nudity in the public sphere or vice versa? Simple offense examined by Richard in his blog seems to be no more complex than the political value I examine here. There seems to be no ideal nor legal precedent for modern nudity laws other than social inertia. Simply because current social standards applied by the average person include covered genitals at all times within the public spaces, and have been for generations, no judge would side with my argument. I would have to prove I am more grievously harmed than a simple loss of expression - as I am not allowed to burn the flag either.
Just because something is common doesn't make it right nor is an unexamined life worth living.