There is a long-standing precedent in Common Law that stipulates the prosecution cannot raise the character of the defendant unless the defendant raises it first. The concept rests on the principle that a person’s character is not relevant to the fact of whether or not they committed an offence unless they make it relevant by making it part of their defence.
It is this basic principle of fairness we should, and generally do, apply to our politicians when assessing the relevance of their private lives. The sex lives of our politicians should not be a matter of public interest unless they have made people's sex lives a matter of their political concern.
The problem facing many conservative politicians around the world is a huge element of their political capital is formed by suggesting matters of sexual morality are actually matters of political consequence. By actively campaigning on issues, and presenting their own morality as evidence of an adherence to the values they claim to promote, they have immediately made a conscious decision to present their personal proclivities as a grounds for which they should earn their constituent's vote.
A failure by them to then adhere to the moral standard they have propagated is not attacked for its apparent moral failing but instead due to the politician’s undeniable hypocrisy and simple false advertising.
Ultimately the voter is faced with two propositions. Either the politician was not saying what they believed, or they lack the capacity to do what they believe. Either of these revelations are entirely relevant to a voting public and therefore unreservedly disclosable.
There are of course plausible scenarios where this same rule could easily apply to those on the political left of the spectrum however this is more likely to apply to other matters which appear incongruous with their overt political declarations such as financial affairs or the running of a business.
Those on the left have traditionally abstained from any legislated interjections into sexuality, with the exception of attempts to further liberate it, and therefore have reasonable grounds to claim their own sexual activities should be afforded the same comparable exclusion from public concern.
Barnaby Joyce injected the sexual affairs of Australians into political discourse when he suggested the life saving HPV vaccination could encourage promiscuity in young women. He made the intimate relationships of others fair topic for public discussion when he supported a plebiscite on marriage equality. He made his marriage and his worth as a father a relevant fact for his constituents every time he promoted himself on a platform of “family values”. He made the semantic details of a sexual relationship a matter of legal concern when he championed a crackdown on welfare cheats who didn’t accurately declare their change of living arrangements.
Having one’s intimate affairs being deemed a matter of political and public debate must be a traumatic experience. For any politician that wishes to escape this fate a simple solution avails itself; never make the intimate private affairs of others a matter for your political concern and we won’t make yours a matter for ours.