In a country where everybody dresses their part, the costume chag should be a great leveler. Purim sees much of Jewish Israel exchange our normal clothes for garments we never normally wear, and in a sense, we’re united by our silliness.

It’s a perfect way to start spring. The heavy repentance themes of Rosh HaShanah are long behind us, the earnest fast of Yom Kippur is over and the hard work of Passover is yet to begin.

It’s Purim and it’s party time. At last, a festival that all of Jewish Israel, regardless of religious differences, can celebrate in broadly the same way.

If only.

This is the vision that I walk around with in my head every year until I go into the costume shops and thud, I’m brought back to reality. During the week that marks International Women’s Day, off I go past the slides, climbing frames, seesaws and other items that these stores focus on for most of the year, to see the massive displays of their seasonal moneymakers — ready-to-wear outfits.

The kids’ outfits are next to the women’s section, where there are leather-trimmed French maid costumes with fishnets, outfits for provocative policewomen and slutty nurses and even suits for Santa’s seductive helpers. Just a few yards from the kids’ fireman and astronaut outfits, some of these women’s costumes even come complete with whips and cuffs.

The sexualization of Purim is partly just a matter of convenience. The easiest and cheapest way for Israeli businesses to stock outfits for this once-a-year surge of demand is to import those made elsewhere for Halloween, and many of these are risqué.

While characters related to the Purim story, or the Bible, are obvious choices for many diaspora Jews when thinking about costumes for the festival, they have become rarer and rarer in Israel as Purim stores here have become outlets for foreign leftovers. The common adult women’s outfits (some of the smaller-sized ones are being scarfed up by teens) have nothing to do with Jewish themes. They are cheerleaders and skimpy Alice in Wonderlands and anything that involves a corset.

The change in tastes for costumes isn’t just due to the market being bombarded with Halloween leftovers; it also reflects something happening on the side of the customers, namely a deeper change that is taking place regarding the celebration of Jewish festivals in Israel. With a huge selection of foreign television piped into their homes by cable and access to the Internet, people are more and more aware of the details of how life is lived abroad, especially in America.

Halloween is one of the big annual events on American sitcoms such as “How I Met Your Mother” and “30 Rock,” in which characters say in so many words that Halloween is a festival for women to dress sexy. For many Israelis, emulating what they see as the American way of dressing up is more natural than recreating traditional Jewish dressing up.

Jeffrey Woolf, an historian and expert on religious observance in Israel, remembers a day “when most people dressed as figures from the Purim story or as soldiers or charedim, or as contemporary local figures — I remember when people were little Moshe Dayans and Menachem Begins.”

Woolf, a rabbi who teaches at Bar-Ilan University, is American-born and follows a very modern strand of Orthodoxy, embracing much of Western culture. But in the case of Purim he thinks that “the tsunami of Western society is basically washing away our own memories — you don’t see the Esthers, or even the Vashtis and the Ahasueruses. It’s the side of globalization that doesn’t respect local culture.”

He adds: “It’s not that we need to be uptight. Even cross-dressing, which is usually frowned on, is accepted on Purim, but there’s a limit.”

Woolf says that he sees the sexualizing tendency seeping from adults even to preteens. “There’s a sexualization of children here, as well as an objectification of women,” he comments, noting that he has seen grade school kids dressed in “very sexually charged” outfits.

Sometimes, the impact of foreign ways on the marking of festivals is innocuous, and actually adds some variety to their celebrations. For example, though I’ve identified myself on these pages as a bit of a doughnut grinch, it’s good to see the market expanding and U.S.-style doughnuts with thick, colored frosting now competing with Israeli-style doughnuts for shop space on Chanukah.

Yet, I have to agree with the international women’s Zionist organization WIZO, which has in the past written to some of the costume companies rebuking them for selling items that are “near pornographic.” I share this concern about how the Purim costume market is impacting the way that women are expected to appear at this time of year — especially as father to three girls. But I think the Halloween-ization of Purim is sad for another reason — because of its impact on community cohesion.

Israeli Jews spend the entire year letting the way they dress define them: Charedim dress one way, religious Zionists another and so on. If you see a roomful of people during the year, you can instantly tell who is who, and people often stick with their own group. On Purim in the past, people shed these uniforms, donned fancy dress and dropped their labels for a day. In the streets, religious Queen Esthers and secular Queen Esthers, who would normally be unlikely to talk would compare notes on how make-believe royalty is treating them.

This week, however, I saw two girls, one religious and one secular, on their way to their school costume parties, which take place during the run-up to Purim. They were in costume, dressed in traditional and risqué outfits, respectively; one was the biblical figure of Yael, the heroine from the Book of Judges; the other a superhero in a skimpy outfit. The camaraderie was absent; not even a smile was exchanged. They went their separate ways to their separate celebrations of what has become, for each of them, a very different festival.

Nathan Jeffay’s column appears twice a month.