It claims to represent 2.2 million, as over a third of adult American Jews, including many who are not synagogue members, state affinity with Reform, making it the largest Jewish denomination.

Reform Judaism foresees a future Messianic Age of peace, but without the coming of an individual Messiah or the restoration of the Third Temple and sacrificial cult in Jerusalem.

During its "Classical" era, roughly between the Civil War and the 1930s, American Reform rejected many ceremonial aspects of Judaism and the authority of traditional jurisprudence (halakhah), favoring a more rationalistic, universalist view of religious life.

"New Reform", from the 1937 Columbus Declaration of Principles and onwards, sought to reincorporate such elements and emphasize Jewish particularism, though still subject to personal autonomy.

In 1983, in the United States, it recognized Judaism based on patrilineal descent, affirming that offspring of a single Jewish parent (whether father or mother) would be accepted as inheriting his status if they would demonstrate affinity to the faith.

These measures made Reform the most hospitable to non-Jewish family members among major American denominations: in 2006, 17% of synagogue-member households had a converted spouse, and 26% an unconverted one.

Orthodox and Conservatives rejected the validity of Reform conversions already before that, though among the latter, the greater proclivity of CCAR rabbis to perform the process under halachic standards allowed for many such to be approved.

The Union consists of four administrative districts, West, East, South and Central, which in turn are divided into a total of 35 regional communities, comprising groups of local congregations; 34 are in the United States and one represents all those affiliated with the Canadian Council for Reform Judaism.

The RAC advocates policy positions based upon religious values, and is associated with political progressivism, as part of the vision for Tikkun Olam.

Tikkun Olam in Hebrew means “repairing the world.” The denomination is also supported by the Women of Reform Judaism (formerly, the National Federation of Temple Sisterhoods).

The 2013 Pew survey assessed that 35% of Jews in the United States consider themselves Reform (the 2001 AJC poll cited 38%); based on these figures, Steven M. Cohen estimated there were 1,154,000 identifying non-member adults in addition to those registered, not including children.

Reform-like ideas in the United States were first expressed by the Reformed Society of Israelites, founded in Charleston, South Carolina, on 21 November 1824.

It was led by Isaac Harby, Abraham Moise, and David Nunes Carvalho, who represented the younger, Americanized, and religiously lax generation in the Congregation Kahal Kadosh Beth Elohim.

On their first anniversary, Harby delivered an oratory in which he declared Rabbinic Judaism a demented faith, no longer relevant, and that America was "the Promised Land of Scripture."

Wise introduced family pews for the first time in known synagogue history (by random, when his congregation bought a church) in Albany on Shabbat Shuvah, 3 October 1851.

Many other German rabbis crossed the ocean to the land where their religious outlook, free from state intervention or communal pressures, could be expressed purely.

The so-called trefa banquet, while apparently the decision of the Jewish caterer and not of Wise himself (who observed dietary laws), prompted protests from the few American traditionalists, like Sabato Morais, who remained outside the UAHC.

A series of heated exchanges between him and Reform's chief ideologue, Rabbi Kaufmann Kohler, encouraged the latter to convene an assembly which accepted the Pittsburgh Platform on 19 November.

A small group of conservatives withdrew from the UAHC in protest, joining Kohut, Morais, and their supporters in founding the Jewish Theological Seminary.

The massive immigration from Eastern Europe, bringing over two million Jews who had strong traditional sentiments in matters of religion even when personally lax, dwarfed the UAHC constituency within a generation.

In contrast with the coolness toward Zionism expressed by Classicists – emanating both from their rejection of old Messianic belief, involving a restoration of the sacrificial cult in Jerusalem, and commitment to emancipation – many new clergymen, like Abba Hillel Silver and Stephen Wise, were enthusiastic and influential Zionists.

Anti-Zionist Reform rabbis broke away during WWII to found the American Council for Judaism,[14] which declined in activity following the Six-Day War.

The selective "return to tradition" encouraged many Americanized Eastern-European-descended Jews to flock to Reform congregations in the postwar years, rapidly swelling the membership ranks of the UAHC.

[15] In 1990, the Union of American Hebrew Congregations and other major Jewish-American organizations asked that Nelson Mandela clarify his pro-Palestinian views prior to his visit to New York City.

The UAHC's senior vice president Albert Vorspan said that "We are hoping to clear the air and defuse the situation so that Mandela's visit...is what it ought to be: a great welcome for a liberation hero without a lot of marginal controversy."

– discuss] KESHER (from Hebrew קשר 'linkage', 'connection') is the now-defunct college outreach arm and campus student organization for Reform Judaism.