It's often said the South Australian senator, Nick Xenophon, is the joker of the Senate, such is his enigmatic ability to extract a deal from the government at a time of maximum vulnerability. Fielding, then, is surely the clown, given his erratic performance, especially over the past two years, and his hamfisted attempts to deal himself in, a la Xenophon. The government considers him a sad joke. So, increasingly, does the opposition. And the punters think he's so hilarious – or just confounding and weird – they confuse the ramblings of the real Fielding with the loony impersonations of his Twitter impostor, “Fake Fielding”. The Senate is a curious club that engenders camaraderie and respect among senators of different ideological complexions. The theatricality of the House of Representatives always draws most media attention. But the Senate is the chamber of true ideological combat, where bills are pulled apart and stitched back together and where dissent from the party line is more likely to be tolerated and encouraged.

It is true that the Senate all too often divides and votes along party lines, in a way that does not serve its original purpose as a states' house of review. But occasionally it gives rise to a debate about a proposed law that restores faith in the capacity of the legislative process to transcend politics. We saw such an occasion last week when the chamber debated the government's paid parental leave scheme. Debate between the major parties has focused on the differences between Labor's scheme (18 weeks paid at the basic wage) and the Coalition's (26 weeks of paid leave funded through a tax on big business). Both policies have their merits. Fielding, it seems, tried to get maximum personal attention by clawing his way through the middle of the debate with a puerile attempt to turn the paid parental leave argument into one about abortion. Now plenty of people in the Senate, regardless of their political persuasion, have very strong views about abortion. They are views that have, from time to time, been argued loudly in the chamber and in debates – or just in response to media questions – outside the Senate.

Among them is Barnaby Joyce, the Jesuit-educated and Catholic-raised Queenslander. Joyce's views on abortion (he is opposed to it) correspond with those of many men in both the Coalition and the Labor Party. Women MPs and senators, by and large, are more likely to hold pro-choice views. Abortion is regarded in parliament as a matter of conscience that is most appropriately argued passionately and in context, but not politically. Those who already held serious reservations about Fielding's judgment and political approach but who had nonetheless continued to give him the benefit of some doubt, have now written him off. But what did Fielding do to so incense them? He claimed, without any evidence, that women of poor character – drug addicts and welfare cheats, for example – could rort the paid parental leave scheme by getting pregnant and having later term abortions. Consequently, he argued the legislation should be amended so an abortion could not be defined as a still birth.

“Most incredibly even prisoners and prostitutes are valued more highly than stay-at-home mums. The scheme would be open to rorting by people who chose to have later abortions,” Fielding said. “Under this bill drug addicts and welfare cheats can rort the system and get paid parental money for nothing. Drug addicts and welfare cheats can go out there and get themselves pregnant and then after 20 weeks have an abortion and still pocket the government cash.” Fielding's comments were, appropriately, greeted with an avalanche of outrage from across the Senate. Joyce, as I've said here previously, is no stranger to shooting from the lip in an effort to win the oxygen of politics – media attention. But he has never been a slouch when it came to Senate debate and he has frequently swum upstream, against the Coalition flow, on issues of principle. Where others have previously lauded Joyce as a terrific communicator, I have been more of a sceptic. Last week, however, he convinced me that when he sticks to what he is good at – analysing policy and principled debate – instead of just seeking the limelight, he is indeed to be reckoned with.

“These amendments do not create an assurance; they create a wedge. These amendments bring into this chamber an issue on which there are deeply held beliefs around the parliament. It is a conscience issue. The way in which this issue has been introduced takes the debate to a base level. You know full well that if you bring the abortion debate up then a bit more diligence is required than you have shown with the process you are following here. I am disgusted by the mechanism of this. An assurance has been given. We have actually been doing the footwork – asking people and getting the assurances across parliamentary lines on this issue,” Joyce said. “I find it one of the more base forms of politics to bring up an issue that you know full well, Senator Fielding, is held as an absolutely primary issue by so many people around this place. I really question the motives you have at the forefront of your mind in bringing this issue forward in this manner.” Joyce concluded by asking if Fielding's tactic was “merely a political ploy”. “If it is,” Joyce said, “I think it is absolutely disgusting.” Greens leader Bob Brown went on to declare Fielding “almost irrelevant.”

“Done, finished and out,” he said. Goodbye.