Deputy Prime Minister and strident moralist Barnaby Joyce argued on the ABC last night that he regretted the breakdown of his marriage and considered it one of the greatest failures of his life.

I am not sure that I'd necessarily call the breakdown of a marriage a failure, but Barnaby did, so for now I will run with that.

But the breakdown of his marriage was not his only failure -- and arguably not his worst.

Read more from Subversive Sam: Royal wedding? For God's sake, get a life!

As Barnaby said during the interview on ABC TV, marriages break down.  While such breakdowns are lamentable, they are not rare and are growing in frequency. While neither Joyce nor I are suggesting this is a good thing, it is a fact of life and a reflection of the changing world we live in.

But Barnaby's failure to protect his estranged wife and daughters after the breakdown of the marriage is not, at all, a fact of life. It is a failure of catastrophic proportions.

To impregnate his girlfriend so soon after the separation -- and possibly before the fact -- is a much bigger failure. It is a failure in moral standards and, quite possibly, of the safe-sex message that he should be communicating.

People grow apart, but that does not mean one of them should rush out and impregnate another.

Barnaby's failure to live up to the moral standards that he promotes as leader of perhaps the most conservative political party in the country -- well-known for its commitment to and promotion of family values -- is a much bigger failure than the breakdown of his marriage.

Barnaby has promoted some of the most conservative social views ever aired by politicians in Australia, but continues living as he sees fit.

It's easy to take a moral position, but it is much harder to live in accordance with that moral position.

Barnaby Joyce is a failure in terms of the full disclosure that he so vocally demands of others.

He was asked on the ABC whether his new girlfriend was an employee of his when the relationship started. He took ''the fifth'', suggesting that personal things should remain personal. That is well and good -- I agree and don't even know this woman’s name (nor do I care) -- but his application of government allowances and a relationship with an employee in a weaker position is not a personal matter, especially for a public figure on the public profile.

It is all too easy for Barnaby to take ''the fifth'', but he has a responsibility to fully disclose matters of public interest.

I have no interest in the nature of Barnaby’s new relationship and I believe his new lady deserves absolute privacy. The publication of her photograph on the front pages of newspapers was in no one’s best interest, other than those selling newspapers. She is not a public figure and is not accountable to the media or the community for her actions. She should be left alone, and her child has the right to grow up without unwanted media attention.

As usual, I suspect the media had no interest in the rights of the mother-to-be. They would not have considered the stress this might put on her and, therefore, her child. Even if she should have known better, there is no justification and no public interest involved in bringing her into the spotlight.

Barnaby is another matter.

There is a very real public interest in how our Deputy Prime Minister treats his wife, how he uses his allowances, how he uses his time and how he uses his authority in the workplace.

There is also a real public interest in any mismatch between his moral protestations and his behaviour. This goes directly to the character of the man.

Barnaby Joyce has no right to hide behind his girlfriend's right to privacy. He chose to be a public figure and while he is not responsible for the conduct of his wife or girlfriend, he is responsible for his own.

I have done some regrettable things in my life. During and following relationships, I've behaved in ways that I am not proud of. I've started new relationships before ending old ones. But I take responsibility for these mistakes and would never try to hide behind the privacy rights of others just to protect myself.

Barnaby talks a lot about people taking responsibility for their behaviour.

Well Barnaby, why not practice what you preach and take responsibility for your own behaviour?