September has long been the best month for fashion. It kicks off with the arrival of Vogue — this year’s mammoth issue clocks in at a glorious 832 pages — and reaches its peak with New York Fashion Week, which starts today.

But this year, instead of embracing September with my normal unabashed sartorial glee, I’m bracing myself for a frustrating fall season.

That’s because in recent years, the political-correctness police have increasingly turned their frenzied attention to fashion. Claiming designers and consumers are engaging in “cultural appropriation,” these critics seek to impose their censorious will on the runways.

If these moral prudes get their way, not only fashion but culture as a whole will suffer.

It’s impossible to understand why the PC police pose such a big danger without first understanding the cultural importance of fashion itself. Famed designer Valentino’s creative co-director Maria Grazia Chiuri put it well this month, declaring that “fashion becomes culture by going beyond an image — by proposing values and conveying emotions.”

In other words, fashion succeeds, both culturally and commercially, when it taps into something common or, better yet, universal in the human experience.

It’s simultaneously individual and communal. Creation and expression don’t end when designers finish a garment; that process continues as women choose what to buy and how to wear it. Done properly, fashion is liberating, an exercise in free speech and free thought.

With good reason, September’s Vogue, featuring Beyoncé on the cover, makes much of the “democratization of fashion.” The Internet and social media have exposed today’s designers and consumers to a wider range of cultural influences than ever before. We’re enriched by this.

And while each culture has its own aesthetic take, the basic themes remain the same. As Chiuri hints, we consider common values, emotions and experiences. Fashion’s message is fundamentally humanizing.

Vogue taps gently on this reality in its profile of Beyoncé. Cultural critic Margo Jefferson describes Beyoncé as a “shape-shifting virtuoso” capable of channeling such diverse icons as Josephine Baker and Rita Hayworth, Naomi Campbell and Audrey Hepburn.

Through fashion as through music, Beyoncé seeks to reach a wide array of audiences. Jefferson writes that as a fashion icon, Beyoncé’s “appropriation and assemblage are based on the understanding that a mass audience is a mass of niche audiences. Each has its own history, with its own desires, and she empowers them all.” Stella McCartney chimes in, adding that Beyoncé’s appeal “crosses art forms, genders and generations.”

That’s fashion’s power — not only in the hands of a master diva walking the runway, but also when worn intelligently by the average woman walking down a New York City street.

To understand how hollow fashion becomes without the enrichment of diverse cultures, look no further than model Kendall Jenner, also heavily featured in this month’s Vogue.

While Beyoncé offers cultural substance, drawing from a range of influences, Jenner signifies nothing so much as her family’s worship of celebrity. She’s less a muse and more a human hanger. Because of the lack of cultural depth, what she wears is no longer fashion — it’s just clothes. In Jenner’s hands, couture isn’t about artistic expression — it’s just shallow materialism.

But Kendall Jenner is the perfect preview of where PC police, if triumphant, will ultimately land us.

Perhaps their intentions are pure: They claim that when designers draw on inspiration outside of themselves, they’re actually engaging in “cultural appropriation,” an act of exploitation or thievery.

This critique ignores how art has always drawn on outside inspiration. Though individual innovation is key, the creative class stands on the shoulders of giants at least as much as scientists. Because fashion continually builds on itself, it’s often impractical, if not impossible, to identify true origins.

So what do critics of cultural appropriation suggest? That we shop with an anthropologist at our side, just to make sure we understand the history and nuances of every fabric and form? That designers mail off royalties to the long-dead, or perhaps that they include an annotated bibliography (Chicago Style preferred) alongside the laundry instructions on each individual garment?

Instead of encouraging consumers to weigh the cross-cultural morals and values embedded in fashion, these critics end up ghettoizing aesthetic expression by race and ethnicity. They narrow our exposure. Instead of encouraging conversation, they restrict it or shut it down altogether.

In doing so, they turn fashion inward. When cultural appreciation is confused with cultural appropriation, self-absorption becomes the safest bet.

Jillian Kay Melchior writes for National Review as a fellow for the Franklin Center, Independent Women’s Forum and Steamboat Institute.