Some people believe religion and politics should not mix. But Rabbi Jonah Pesner, senior-president of the Union of Reform Judaism in North America, is not among them.
His keynote speech to Liberal Judaism's biennial conference at the weekend was a stirring call to action. "To be a Progressive Jew is to put a stake in the ground for a political vision of a just society," he declared.
It was not enough to volunteer in soup kitchens or take part in Mitzvah Day, he argued. Progressive Jews should join other faith groups and work across party political lines to tackle injustice.
He hailed Liberal Judaism's achievement in being the first synagogue movement to pledge to pay a living wage and its involvement in the grassroots campaign group, Citizens UK.
His address, blending personal anecdote and prophetic passion, set the mood for the event, chiming with Liberal Judaism chief executive Rabbi Danny Rich's declaration that "social justice is the key component to messianic realisation".
There is a feeling that we are moving forward
But, along with the workshops, study groups and Shabbat worship, there was time to relax at the bar, if not enough for a round of golf at the Wokefield Park Hotel venue, near Reading.
"There is a mood of celebration here, a feeling that on a number of issues we are moving forward," said Robin Moss, 27, one of four under-35s on LJ's board of 13. There was, he added, "a self-confidence around the movement - a lack of apology. We are not 'not Orthodox' and not 'not Reform'. We use the traditions and Jewish historical experience, combining these with modern values to have an authentic form of Judaism that works for the 21st century."
There was a record attendance of more than 300 delegates. The movement is shortly to welcome its 40th community, York, into the fold. Investment in new regional groups, such as Gloucestershire - where outreach director Rabbi Anna Gerard has taken up residence in Stroud - has paid off with rising numbers. Liberal Judaism's 10,000-plus membership was up by three per cent last year from 2012.
When Gillian Wolfe retired to Stevenage with her husband Terry four years ago, they started the North Herts Liberal community. It now has 48 members and managed to attract 38 of them to one Friday-night dinner. "Because of the conference, I have some new ideas to attract new members," she said, producing a notepad with a list of 16 points.
The latest graduates of the movement's Baalei Tefilah course to train prayer leaders received their certificates. A new group of Emerging Jewish Leaders for congregations was launched, as was an online resource bank where communities can find publications, music and programme ideas.
The appointment of LJ board member Gillian Merron - who was present throughout the conference - as Board of Deputies chief executive was greeted as an example of Liberal Jews making their mark in the wider community.
Liberals were no more "an outlier of anti-establishment Jews", said Mr Moss, who works professionally for the UJIA.
But they were also keen to emphasise that a willingness to work cross-communally did not come at the expense of their radical roots.
"Our advocacy of equal marriage," said Rabbi Rich in a conference address, "was not about media popularity but about righting an historic injustice… Our critical friendship of Israel is not about pleasing this party or that or salving our consciences but it is about declaring that there are universal values of conduct."
LJ chairman Lucian Hudson said that the movement had "broken new ground by providing mixed-faith blessings and welcoming the children of such couples on an equal basis, regardless of the gender of the Jewish parent".
Reform chairman Robert Weiner, who attended, said: "It's been a good few days. Liberal Judaism should be very proud of what they have put on."
While there was cause for congratulation, the conference examined challenges, too. A green paper prepared by the chair of the Liberals' Rabbinic Conference, Charley Baginsky, mentioned low synagogue attendance and some members' desire for more positive promotion of Israel.
The paper asked also asked if its liturgy should take into account "that many members struggle with traditional views of God and are more inclined towards religious humanism".
One session featured the charismatic Professor Fania Oz-Salzberger, co-author of the recent book Jewish Words with her father Amos Oz. She even contemplated whether it was possible to have Jewish life without God at all. "My twin boys are fifth generation non-believing Jews and they are still going strong," she said.
