The modern art world suffered another of its periodic embarrassments recently when a visiting high school student at the San Francisco Museum of Modern Art set his glasses down on the floor against a bare wall and walked away, whereupon museum patrons took it to be the latest avant garde masterpiece, crowding around it while striking chin-pulling poses and snapping photos.

Although the prank was quickly exposed, art fans defaulted to the usual confusions about the quintessentially modern question — what is art? — with not a few concluding that in context it wasn't a prank at all, but a legitimate new artistic expression. Never mind that the same teenager had previously punked art-goers with a baseball cap and a trash can placed in exhibit spaces.

This kind of radical subjectivity has at last spilled beyond modern art galleries and clattering coffee houses into the real world of law and politics with the recent elevation of transgender rights to the top of the national agenda.

Before there had been much public discussion about what being "transgender" means, and while the dust was still settling on the Supreme Court's belated discovery that same-sex marriage was sitting there all along in the due process clause of the 14th Amendment, the plight of the transgendered suddenly became the urgent frontier for civil rights protection.

Unlike gay rights and same-sex marriage, which moved slowly from the ground up in state and local venues and courthouses for decades while public opinion crystalized, the issue of transgender rights was immediately elevated and centralized in Washington, with dictates issued from the Justice Department and Congress drawn into the fray.

Has there ever been a social issue that erupted into a national controversy this swiftly, especially about a proximate issue — bathrooms — so seemingly remote from our most pressing national priorities?

Last year, the defense secretary announced the formation of a working group aimed at lifting the ban on transgender troops openly serving. (AP Photo)

It's an issue that has gone beyond bathrooms and has managed to find its way into a number of federal policy areas. Last year, Defense Secretary Ash Carter announced the formation of a working group aimed at lifting the ban on transgender troops openly serving.

On Capitol Hill, Democrats have pushed gender-related protections into spending bills this year, which scuttled the energy and water appropriations, prompting the GOP to limit amendments so other bills can pass.

The "perfect storm" imagery is overused to the point of cliche, but this is one case where the cliche fits the need of liberalism to find new victim classes over which to extend its protections. It presents several social and legal issues of great importance.

Modern medicine makes it possible for someone to "switch teams" through sex-reassignment surgery and hormone treatment, and a non-trivial number of people have done so over the years, generally reporting themselves to be much happier.

Reliable statistics are hard to come by, but some estimates run as high as 25,000 people a year undergoing reassignment surgery worldwide, with male-to-female changes outnumbering female-to-male by about three-to-one.

Individuals who undergo complete reassignment surgery are like the pig in the bacon-and-egg breakfast joke (the chicken is involved while the pig is committed), and beyond the Rubicon-crossing transsexuals are the numerous individuals whom we once called "cross-dressers" but whom we now call transgender.

There is a certain "fluidity," a term prominent in gender identity vocabulary, to the whole scene. For some individuals, it is the first step on the way to complete reassignment, while at the other end of the spectrum it might be thought of as performance art, or keeping one's options open by retaining your "membership," so to speak.

Allowing bathroom access according to whatever gender you self-identify with is the explicit policy on most campuses today, generally without much fuss. (AP Photo)

Never mind Caitlyn Jenner (around whom there are conflicting rumors that she wants to switch back to being male Bruce again); one thinks of Corporal Klinger in the old "M*A*S*H" TV series from the 1970s, whose donning of a dress was a dodge to get discharged on a mental illness rap.

Just as old editions of the American Psychiatric Association's Diagnostic and Statistical Manual categorized homosexuality as a mental illness, until recently the APA likewise categorized transgender individuals as suffering from "gender identity disorder."

The latest edition, DSM V, has changed this to "gender dysphoria" in an attempt to eliminate the stigma of supposing gender indeterminacy to be a mental health problem, even though there are many doctors and psychiatrists who continue to believe most cases of gender ambiguity are a psychological disorder, and one of the frequent campus demands is for enhanced counseling for "transgender mental health issues."

Given that it is indeterminate transgendered individuals who are at issue in the Great Bathroom Wars of 2016 (people who have gone all the way with sexual reassignment surgery don't have a bathroom problem), how prevalent is it? The DSM V estimates the rate of transgendered adult males at 0.005-0.014 percent, and 0.002-0.003 percent for adult females.

This range yields a rough estimate of about 30,000 transgender individuals in the United States. A 2015 Census Bureau estimate placed the number closer to 90,000. Either number represents a relatively tiny fraction of Americans.

(There's one outlier estimate of 700,000 transgender individuals by the Williams Institute at UCLA Law School, but this appears to be like the homeless population estimates of the 1980s that exaggerated homelessness numbers by an order of magnitude. Prediction: There will be intense lobbying for including the transgendered as an official category in the 2020 census. Canada's census bureau is already revising its questionnaire for 2021.)

Given that small number you might think a big, diverse country like the United States could muddle along and figure out how to respect and accommodate this population, albeit with lots of fits and starts and unhappiness all around.

Suddenly, believing in separate bathrooms for men and women became the moral equivalent of separate drinking fountains under Jim Crow. (AP Photo)

A transsexual person I know wrote to me recently: "Regarding bathrooms, I believe trans folks need to be respectful. During transition at work I used a single, locked visitor's bathroom until after surgery. In public situations I carried a letter from my psychologist explaining my situation, but never had to show it. I know my experience doesn't cover all the bases but I also never felt 'entitled' or expected society to rearrange their affairs because of me."

This person is actually a conservative, and I know of several other conservative transsexuals. But they don't represent the dominant perspective on the issue. For that you need to visit a college campus, where an ideological fetish for transgenderism thrives, often connected to the old-fashioned leftist narrative about the oppression of "neo-liberalism" and "patriarchy."

Allowing bathroom access according to whatever gender you self-identify with is the explicit policy on most campuses today, generally without much fuss. The heart of gender studies today goes well beyond sensible questions about historic stereotyping of gender roles and their "social construction," to the radical view that rejects the idea of human nature itself.

The subjectivity at the heart of collegiate transgenderism can be seen in the instability of the root acronym. Whereas it used to be referred to as the LGBT (lesbian-gay-bisexual-transgender) community, today there is a riotous diversity of acronyms that are starting to look like the names of Welsh villages.

At Bowdoin College in Maine, for example, you will find LGBTQIA in use, while down the road at Bates College it is LGBTIQQ. The most prolix was Wesleyan University in Connecticut, where the all-gender residence hall advertised itself as a "safe space" for LGBTTQQFAGPBDSM people. (This acronym was scrubbed from the university's website last year after having been in use for a decade.)

At the bottom of this shifting alphabet soup is the view that gender is unrelated to biology, but is a wholly artificial social construct. Moreover, gender isn't a binary matter — men and women, heterosexuality and homosexuality — but is a broad and apparently shifting spectrum of "identities."

It is not widely appreciated yet that same-sex marriage and even transsexual team-switching represent the right wing of sexual politics today: At least married gays and lesbians are embracing a central institution of the bourgeois middle class, while transsexuals typically take on the conventional characteristics of their new sex.

The gender identity crusade has gone as far as to demand that birth certificates should leave the sex of newborns blank, so that everyone can choose their own gender later. (AP Photo)

The new frontier of what I call "human nature denialism" believes that your sex is as much a matter of willful choice as what color shirt you wear, never mind those functional genitalia that DNA has bestowed on you, and we're up to as many as 50 different categories of made up gender pronouns.

The gender identity crusade has gone as far as to demand that birth certificates should leave the sex of newborns blank, so that everyone can choose their own gender later. In other words, whether you want to be a man or a woman, or something in between, is now a matter of personal preference.

The rejection of human nature is not just a strong skepticism or allowance for the diversity or mystery of human types, but an active hostility toward human nature, which can be seen in the way the designation "cis-gender" (defined as "people whose gender identity aligns with the sex they were assigned at birth" — note the telltale term "assigned") is considered just one among many possible choices on the menu, but very often as a term of derision. And the matter is considered settled.

By degrees, transgender ideology has broken out of its campus hothouses through several local political initiatives.

The first to gain national attention was in the city of Houston, where the city council in 2013 passed an ordinance aimed primarily at protecting gays, lesbians and transgender individuals from discrimination in employment and public accommodations (restaurants, hotels, etc.), but which also included a gender-identity provision enabling bathroom choice that incited the bathroom access issue for the first time. (Similar ordinances in as many as 200 other cities have been implemented without much controversy, though not all of them specifically included the bathroom proviso).

A group of Houston clergy, many from black churches, spearheaded a successful petition drive for a referendum to repeal the ordinance, which Houston voters passed by a nearly two-to-one margin last fall. Although the vote attracted national attention, there were no calls for corporate or sports boycotts of Houston in the aftermath, and no demands for any kind of federal intervention.

The Human Rights Campaign and Equality North Carolina released the names of company executives who have signed on to a letter criticizing the law and seeking its repeal. (AP Photo)

That was not the case a few weeks ago after the North Carolina legislature overrode a non-discrimination ordinance passed by the city of Charlotte that included a gender-identity provision raising the same bathroom access question.

In the aftermath, several major corporations including PayPal and Deutsche Bank made public announcements that they would boycott North Carolina (even while expanding their presence in Middle Eastern countries where homosexuality remains a capital offense); the NBA said it might move the 2017 All-Star game slated for North Carolina to another state; and a series of musicians and artists including Cirque du Soleil and Bruce Springsteen canceled performances in the state in objection to this "bigotry."

Suddenly believing in separate bathrooms for men and women became the moral equivalent of separate drinking fountains under Jim Crow, never mind that six African-American Democrats in the North Carolina legislature voted in favor of the bill overturning Charlotte's ordinance.

Perhaps the state legislature should have stayed out of Charlotte's affairs in deference to local control, just as conservatives wish Washington D.C. would show more respect for state governments. There was talk of a compromise between Charlotte and the legislature, under which each side would back away from their fixed positions and allow the city to keep most of its non-discrimination provisions while the legislature could keep separate sex bathrooms.

This is when national advocacy groups, especially the Human Rights Campaign, entered the fray to oppose any compromise and demand federal intervention. In the blink of an eye by Washington standards, there emerged the sweeping dictate that public schools nationwide had to allow transgender students access to the bathroom of their choice, regardless of their specific biology or anatomy.

It was, Attorney General Loretta Lynch argued, a violation of the proscriptions against sex discrimination in Title IX and the Civil Rights Act of 1964, and school districts that refused to submit could lose their federal funds. It is beyond doubtful that the legislators who included "sex" as a protected category in the Civil Rights Act of 1964 or Title IX understood the term in the capacious way it is right now.

Several local school districts had reached compromises with transgender students whereby schools provided private changing areas in girls locker rooms and single-occupant gender-neutral bathrooms. (AP Photo)

In a remarkable piece of reporting, the New York Times revealed how the Human Rights Campaign and other transgender advocacy groups gathered after the Houston referendum and intensely lobbied the White House to intervene with an uncompromising position.

Several local school districts had reached compromises with transgender students whereby schools provided private changing areas in girls locker rooms and single-occupant gender-neutral bathrooms. This kind of compromise and accommodation is now deemed unacceptable by transgender activists.

The hardening into what might be called "transgender absolutism" reflects the increasingly vindictive temperament of the identity politics Left, surely among the sorest winners in history, in the wake of their rout of social conservatism in the Supreme Court's same-sex marriage decision. Forget compulsory cake baking; we need to liberate bathrooms!

Beyond the questions about human nature and distinctions between the sexes that transgenderism raises are the practical, legal and political questions of whether transgender people should be swept up as a protected class in civil rights law, and if so in what ways. Whether you are African-American or Hispanic isn't a matter of self-identification (unless you are Rachel Dolezal).

But transgenderism is treated precisely on this basis, and according to guidelines for public schools issued by the Human Rights Campaign, it is impermissible to question anyone about their gender identity. Already this is leading to controversy in schools about whether a transgender male can compete on the girls' sports teams through the simple expedient of claiming female identity.

What about the case of a male intending a transition to female but not yet taking hormone treatments? Such a person will have a distinct advantage in girls' sports. There is already a case out of Alaska where a pre-treatment transgender boy/girl is easily winning girls' track and field events.

Exercising common sense on these kinds of cases is certain to generate litigation, and already has. Like many aspects of this issue, the confusion this may wreak on the entire Title IX sports regime has not been thought through very far.

Then there is the way the Obama administration has handed down this diktat. As it has done in some many other areas, it has issued its novel interpretation of old statutes through a "guidance" letter, rather than through a formal rule-making process that would involve public comment and make the formal record a matter for judicial review.

As with many similar initiatives of the Obama administration, this end-run around the Administrative Procedures Act was done precisely because their interpretations and rules would be unlikely to survive the formal rule-making process. These "informal" rule makings lack the full force of law, but the discretionary threat to cut off federal funds is usually sufficient to gain compliance.

While the federal government has often threatened to cut off education funds for non-compliance, it has never yet happened, and probably won't in this case to the many states, such as Texas, that are saying "keep your money." Would the Obama White House really want to defend cutting off school lunches for low-income children in Texas schools?

The fact that the Obama administration and so many liberals regard the matter as easily and fully settled offers a window into the moral soul of the country. It represents the apotheosis of pure willfulness, or the completion of Nietzsche's prediction of the "trans-valuation of all values."

One wonders how long it will be until one of Lincoln's famous logical aphorisms is banned from campus as "hate speech" — "If you call a tail a leg how many legs does a dog have? Four. Calling a tail a leg doesn't make it a leg." Gender dysphoria may be entirely authentic and deserving respect and legal recognition, but does a man calling himself a woman make him such in the absence of medical treatment?

It ought to be possible to extend the principle of equal rights at the center of American political thought to transgender people while still working through legitimate disagreement about the practical implications of this new frontier.

Questioning the new orthodoxy of gender self-identification and sex classifications is to be marked out as a bigot, though as Houston's majority-minority electorate showed, the opinion is not widely shared beyond the college campus and the White House.

And yet one thinks of the aphorism of the Roman poet Horace: Naturam expelles furca, tamen usque recurret — "You may drive out nature with a pitchfork, but she keeps on coming back." The issue of transgender bathroom integration in public schools may well come to resemble the debacle of forced bussing 40 years ago, where compulsory liberalism was forced into headlong retreat by a ferocious public backlash.

It is ironic that liberals who otherwise champion the sanctity of nature when it comes to global warming or endangered species or pristine forests draw the line when it comes to human nature.

Steven F. Hayward is the Ronald Reagan distinguished visiting professor at Pepperdine University's School of Public Policy.