By claiming their support for National stems from their "spiritual values" two former All Blacks are crossing a dangerous line

Michael Jones was one of the greatest All Blacks to ever wear the number seven jersey, but his endorsement of National yesterday was foolish in the extreme.

Jones and Va'aiga Tuigamala campaigned with John Key in South Auckland yesterday, endorsing the National party and attacking Labour for decriminalising prostitution and allowing civil unions. I have no problem with them expressing a personal view and getting involved in the political process. Although their reasoning seems odd given that National's policy on both prostitution and civil unions is identical to Labour's, they have every right to take a stand. For John Key, it was a political coup, a significant step in his efforts to manoeuvre National out of the ethnic cul-de-sac it has been in for decades.

What disappoints me – no, what angers me – is that according to the New Zealand Herald, they based their support for National on "spiritual values".

We have never had to much worry about the separation of church and state in this country. Despite the influence and efforts of our early missionaries, New Zealand governments from the first have never been pressured to adhere to this or that religious belief or faction. Nor are churches required to acquiesce to the state. All New Zealanders are equal in the eyes of the law and most other citizens whatever their beliefs.

That is not to say that churches have not had a profound influence on our political life. From the temperance movement and the right to give women the vote, through to nuclear-free and anti-apartheid campaigns, New Zealand churches have been open anf active players on the political scene. That is to be welcomed and encouraged. As with politics and sport, there is no sensible way to separate politics and religion. People of faith are called to advocate for what they believe, and a democratic country should celebrate their engagement.

The principles of faiths tend not to be negotiable. Every Christian, for example, will want to help the poor. There is nothing more central to the gospels. But when it comes to deciding how to help the poor, Christians will be found on all sides of every argument.

For that reason churches choosing to get involved in politics have long avoided partisan endorsements. They have argued for certain policy concerns over others, but are clear that it is not for them to tell anyone how to vote. Ministers do not want to alienate their congregations, nor do church leaders wish to alienate those who disagree on how to wrestle with the world's injustices. The church is meant to have room for all and God is meant to be far, far bigger than party.

So for Jones and Tuigamala to claim "spiritual values" have inspired their support for one particular party, is irresponsible. Faith should always be political, but never partisan.

In September, the New Zealand Council of Christian Social Services sent an open letter to all politicians, pleading that "those on the margins of society" be central to the campaign. Leaders of the Catholic, Presbyterian, Anglican, Methodist, Baptist and Salvation Army churches argued in the letter "that more action is needed to address the issue of a persistent, damaging poverty that hurts us all".

"When our politicians talk about the policies they plan to introduce we want them to talk about he extent to which those policies can be considered just and compassionate, and we want them to explicitly address the issue of reducing poverty."

There was no mention of party, because faith transcends that. Jones and Tuigamala could learn from that wisdom.