In his years as mayor of New York City, Michael Bloomberg seems to be growing more comfortable in his Jewish skin.

As a candidate for mayor in 2001, he would often bristle when reporters asked about his Jewishness. After a trip to Israel in 2005, by-then Mayor Bloomberg said he was "proud" to be a Jew, but qualified the statement somewhat by adding, "It doesn't make you any better or worse. You are what you are."

But here's what he had to say on Sunday, unveiling his environmental proposals before a conference of ministers at a church in Harlem: "In my faith, the Jewish faith, there is a religious obligation called tikun olam, or to make the world whole, or to correct error and end injustice. And that responsibility is found among people of goodwill in every faith."

I doubt Bloomberg is any more observant or Jewishly knowledgeable than he was six years ago. I bet the difference is the phrase "tikun olam." It is only in the last 20 years that the phrase has fully entered the Jewish vocabulary as a synonym for social action. In that time it has been embraced by all the major denominations. But few use the phrase as enthusiastically as those on the margins of Jewish involvement – or, to put it in a less judgmental way, those for whom the received categories of Jewish involvement – synagogue, mitzvot, fund-raising, Zionism – do not apply. The phrase allows a Jew like Bloomberg to name the impulse for justice and public service in a Jewish way.

That has also made the phrase an object of derision among some – especially critics of Rabbi Michael Lerner, who resurrected the phrase as the name of his liberal Jewish magazine in 1986. Before Tikkun the Magazine, the phrase could be found in the daily prayer book (in the Aleinu prayer), in the Mishna (as a legal remedy), and in Lurianic Kabala (as a sort of karmic, cosmic healing). Jews were doing universal "social justice" going back to the founding of the Bund, but they weren't calling it tikun olam. Even in The Jewish Catalogue, the famous compendium of counterculture, "hands-on" Judaism, the phrase appears but once, and then only in the book's third volume, published in 1980.

Lerner and the magazine attached a specific political meaning to the phrase, making it synonymous with his left-wing views on Israel, the environment, feminism, gay rights, and labor. That led Philologos, the Forward's popular language columnist, to sneer, "Neither in its mishnaic nor its kabbalistic sense does 'repairing the world' have anything to do with the politics of either the left or the right.…"

Philologos also levels another common criticism against the growing popularity of the phrase, calling it "an example of how authentic religious concepts can be cheapened when retooled and promoted for a mass audience."

Despite this, or maybe because of this, tikun olam has become a mainstream "value" in Jewish education, alongside love for Israel, tzedaka, and gemilut hasadim (acts of loving-kindness). The Reform movement's Central Conference of American Rabbis includes the phrase in its latest Statement of Principles, the Conservative movement offers "Tikun Olam Publications" for its youth groups, and Reconstructionists have their Tikkun Olam Initiative.

Even the Orthodox Union uses the phrase, saying the mission of its Washington policy office is to "to work for the betterment of the world – tikkun olam – for all of humankind." Given that the OU often departs from the other movements on church and state and other issues, its use of tikun olam suggests that the phrase has become big enough to embrace all forms of Jewish social action, never mind the politics. Rabbi Jonathan Sacks, the Orthodox chief rabbi of Great Britain, uses the phrase as the opposite of "parochial." He has urged his fellow Orthodox to look beyond their particularistic needs to engage in the wider social and politic debates of the day – in essence, to reclaim tikun olam from the progressives.

Like "schadenfreude" and "sexaholism," tikun olam is one of those phrases that gains currency because it fills a need in the language – and somehow honors the concept it names. Jews have long struggled between their particularistic and universalistic impulses. Particularists feel Jews have their own house to worry about without trying to clean up anyone else's. Universalists believe Judaism has a message for the whole world. Particularists think "changing the world" is a recipe for assimilation. Universalists find tradition too confining to be useful.

Tikun olam nicely splits the difference – at least for the universalists. It gives them a Jewish way to describe their activist choices without committing them to a specific "Jewish" agenda. It elevates the universalistic impulse, placing it on a par with other branded Jewish "pillars": kashrut, prayer, Shabbat. If Jewish values were a sports league, tikun olam would be an expansion team, spreading the game to a new crop of fans.

At its worst, tikun olam does represent a dilution of Jewish tradition, a handy catchphrase that lets the user stamp anything as Jewish. It can absolve the user of seeking a deeper engagement with Judaism.

But let's be charitable – tikun olam also expresses a yearning by its user to see his or her actions as Jewish. It is a statement of belonging, a secret handshake between the activist and her ancestors. It tells the world, just as it tells fellow Jews: I don't feel the same religious obligations as you, but we live in the same place. Let's make it a better place, and in doing so perhaps we'll make better Jews.