David Littleproud

Littleproud was viewed as a potential candidate to replace Barnaby Joyce as National Party leader in February 2018. The position was eventually won by Michael McCormack.[9] On 4 February 2020, following Bridget McKenzie's resignation, he defeated Keith Pitt and David Gillespie to become deputy leader of the National Party.[10][11] The ballot for the deputy leadership was held simultaneously with a leadership spill in which McCormack defeated a challenge by Joyce. It has subsequently been suggested that Littleproud may emerge as a compromise candidate if conflict continues between supporters of McCormack and Joyce.[12][13]

On 14 February 2018 Labor voted with the Greens to disallow a mechanism in the Murray Darling Basin Plan which would have prevented farmers in the Northern Basin giving up 70GL of water which otherwise would have been lost to seepage and evaporation.[14] The disallowance motion triggered a crisis in basin states when New South Wales and Victoria pledged to abandon the Plan as a result. It was widely considered the withdrawal of the two largest states would see the Basin Plan dismantled after it had taken more than a century to strike the agreement.[15] On 7 May 2018, in the lead up to a second disallowance motion that would have blocked 36 environmental water savings projects, Littleproud struck a deal with Labor that both secured the works in question and the 70GL recovery reduction for Northern Basin farmers which had previously been disallowed. This effectively resurrected the Murray-Darling Basin Plan by reassuring Basin states the Plan would be fulfilled as agreed in 2012.[16] In addition to securing the Basin Plan, Littleproud delivered enhanced protections for Aboriginal people in the Basin. This included an Indigenous position on the MDBA board and a world-first $40 million indigenous fund so Aboriginal communities could buy water for either cultural or economic purposes.[17]

Littleproud at a July 2018 meeting with U.S. Secretary of Agriculture Sonny Perdue

Littleproud successfully negotiated with the Senate cross bench for passage of legislation establishing the Regional Investment Corporation. On 6 February 2018 the new laws passed the upper house,[18] breaking a political deadlock that had dragged on months. On 16 May 2018 it was announced that the RIC's headquarters would be set up in Orange, New South Wales, fulfilling in part the Nationals' commitment to deliver public service jobs to regional areas.[19]

In December 2017, Littleproud was one of four members of the House of Representatives to vote against the Marriage Amendment (Definition and Religious Freedoms) Bill 2017, which legalised same-sex marriage in Australia.[20] Littleproud had pledged to vote according to the outcome of the Maranoa postal survey held before the vote, which was run by the Australian Bureau of Statistics. His electorate of Maranoa recorded a result of 56.1% against changing the definition of marriage.[21]