Michelle Grattan, University of CanberraOutspoken Queensland Nationals senator Barry O'Sullivan has declared Barnaby Joyce a “once-in-a-generation type of politician” who remains a big asset to the Nationals despite the sharp grassroots reaction to his affair with his former staffer.With some Nationals reeling from the backlash to the revelations amid speculation about Joyce’s future, O'Sullivan went on the front foot on Monday night.“We’ve not seen any government that has done more for the bush than this one, with Barnaby Joyce as deputy prime minister,” he told The Conversation.“I don’t want to lose one of the best politicians we’ve had in my lifetime. Are you going to shoot your best horse because he jumped the fence and was found in the neighbour’s paddock?”O'Sullivan’s strong defence came as Malcolm Turnbull was forced in parliament to express his confidence in Joyce.When Opposition Leader Bill Shorten asked Turnbull whether Joyce would be acting prime minister when Turnbull visits the US next week, and whether he still retained confidence in Joyce, Turnbull kept his answer as brief as possible.“Yes in response to both questions,” he said.Turnbull is known to be furious with Joyce, whose affair with Vikki Campion, now expecting his child, has dominated headlines and distracted the government since the story broke in the Daily Telegraph mid-last week.Turnbull and his office struggled on Monday to avoid being ensnared, as questions were put about the movement of Campion, who was shifted to the office of Resources Minister Matt Canavan after her relationship with Joyce started to cause problems in his office. Later she took up a position in the office of then Nationals whip Damian Drum. She left government at the end of last year.Under the ministerial code of conduct, a minister’s “close relatives and partners are not to be appointed to positions in their ministerial or electorate offices and must not be employed in the offices of other members of the executive government without the prime minister’s express approval”.The opposition asked whether Turnbull or his office was involved in creating a new position last year in either Canavan’s or Drum’s office.Turnbull said he was advised the Nationals were provided with a number of personal staff positions as a share of the government’s overall staffing pool. “The distribution of those staff members between Nationals’ offices is a matter for the National Party,” he said.“I’m further advised that at no time did the Nationals fill all vacant staffing positions.”The government is arguing that Turnbull was never officially informed that Campion was the partner of Joyce – who remained married to Natalie Joyce – and so the question of prime ministerial approval did not arise.O'Sullivan said the Nationals base had expressed disappointment and frustration at Joyce’s behaviour.“But no-one is challenging his ability to do the great job he has done,” O'Sullivan said. “Do we want to chip away at him until he’s gone?”O'Sullivan, who said he was not personally close to Joyce, has a reputation as a straight talker. Last year he spearheaded the backbench Nationals move that led to the government capitulating to pressure for a royal commission into the banks, which commenced on Monday. He was critical of Joyce’s demotion of fellow Queenslander Keith Pitt in the December reshuffle.Treasurer Scott Morrison told the ABC on Monday night: “There’s no-one I know in the parliament who is a stronger advocate for rural and regional Australia."While events regarding Barnaby’s private life … are disappointing, most importantly to his family and others, that doesn’t change the fact that Barnaby, over a long period of time in his public life, has dedicated himself to public service and the people he represents.”Asked about the code’s provision about partners not being employed without prime ministerial approval, Morrison said Joyce “can’t have two partners at the same time and he was obviously still married”.Michelle Grattan, Professorial Fellow, University of CanberraThis article was originally published on The Conversation. Read the original article.