Left and right. This quirk of revolutionary seating arrangements and eighteenth-century French party lines has come to structure political conversation and debate all over the English-speaking world.

As I talk with ministers here and overseas, I’m hearing that the church is increasingly splitting the same way. Churchgoers must side with the Christian Right or Christian Left. Preachers skirt around political issues for fear of further dividing the church (Hard work for a book as politically charged as the Bible). Parents anxiously enquire about the political affiliation of their children’s suitors.

It’s not that I think there should be only one unified Christian voice in the public square. The problem is that our voices are getting so tediously predictable. I’m on the Left, so I pick the bits of the Bible that make Jesus sound like pre-selection candidate for an inner-city Greens seat. I’m on the Right, so I cycle through my playlist of social conservatism’s greatest hits: sex, bioethics and religious freedom.

All important issues. But is the Christian’s calling really to sit on the sidelines waving weird spiritual banners for our favourite team? Where is the theological alternative to take us beyond the Christian Right and Left?

The best place to start is by unpacking a Christian conception of the ‘common good’.

The ‘good’ part

I take it as obvious that Christians should be thinking about politics. It is our duty as citizens of democracy to render our considered opinions to Caesar; it is our duty as Christians to love our neighbours by seeking their good. On a personal scale that means treating people the way we would want to be treated; on a political scale, that means discerning and advocating what is good for us all.

This is tricky work, and our track record is mixed (as in most things). But it has not been wasted effort. Every time I’m pulled over for a breath test, I remember Bob Hammond. In 1936 he contributed an opinion piece in the Sydney Morning Herald urging tougher restrictions on drink driving.

Our motivation in advocating for religious freedom should never be self-interest, but love.

At the time you could be quite drunk and still legally drive a car. But backed by a formidable feminist union movement — the Women’s Christian Temperance Union — he and others lobbied the government to change the law. You didn’t need to be Christian to see the good here. You didn’t need to be on the Left or the Right to get on board. (Doing something simple about mass preventable deaths had not yet become a partisan issue.)

With access to the mind of the manufacturer, Christians have something unique to offer into the conversation about what makes human life good.

Indeed, historians tell us that some of our culture’s most treasured ideals are heavily indebted to biblical ideas: the inherent dignity and value of all women and men on earth (Genesis 1:27), the importance of marriage and family as a foundation for society (Genesis 2:24, 1 Timothy 5:8), our responsibility to steward creation wisely (Genesis 1:28; Deuteronomy 20:19, 22:6, 25:4), the urgent call to love even our enemies (Matthew 5:43–45), concern for the wellbeing of the poor and dispossessed (Proverbs 14:31, Leviticus 19:33), equal justice for all (Numbers 35:30-34) … we could keep going.

But not every Christian idea can or should be made into government policy.

The ‘common’ part

It should be obvious that the church’s job in political debate is never just to use our numbers to serve our collective self-interest. When we advocate for the humane treatment of refugees, we don’t just mean Christian refugees. When we talk about free speech, we don’t just mean our speech.

Christian lobbyists should never rally their supporters to ‘protect your rights’ or ‘fight for our tax concessions’. Of course the state is accountable to God (Romans 13:1–4), and its duty is not to get in the way of gospel proclamation. Where possible we should persuade rulers of the importance of religious freedom and the quantifiable benefits that non-profit societies like churches offer our communities.

But our motivation in advocating for religious freedom should never be self-interest, but love. Our goal is not the ease of a comfortable Christian life, or the satisfaction of winning a fight. We are driven by something much more important: an urgent concern for the spiritual good of our neighbours. We cannot afford a posture of panicked catastrophising or a tone of shrill defensiveness (something, I’m sorry to report, we are quickly becoming known for).

Gospel work is never to be driven by fear.

Even more importantly, in seeking the common good we will always be selective in what we contribute. Not every Christian ideal can or should make its way into law. Bob Hammond was not trying to force everyone in NSW to abide by his own strict Christian views about alcohol. If you pass out drunk in your own living room, he argued, that’s one thing — but get behind the wheel of a car and you might kill somebody.

Even Moses had to be realistic about what legislation could achieve. Israel’s law contained several provisions around divorce, largely aiming at protecting the vulnerable party (Deuteronomy 24), even though God’s intention was always for marriage to be indissoluble (as Jesus explains in Matthew 19:8).

One of our consistent failures — from no-fault divorce to same-sex marriage, to gender inclusivity — has been our lack of careful thinking about the jump from Christian teaching to social policy.

It might be good for us, but is it good for all?

Without this step — without a clear Christian conception of the common good — we have no way to decide which issues to take on and which ideals to put forward. Without theology driving us, we fall back on party lines. The result is predictable: challenging new questions and well-meaning proposals for progress come up; the Christian Left jumps on board uncritically; the Christian Right recoils instinctively.

My brothers and sisters, this ought not be. Jesus is team chaplain to no political movement — progressive, or conservative.

As a church, we need to start conversations around the common good — both within our community, and with other groups in society. We might just find we surprise ourselves, and each other.

Andrew Judd is an associate lecturer at Ridley College, Melbourne.