As the Liberal and Country League (the predecessor to the South Australian Liberal Party of Australia) descended from a historical merger from an earlier Country Party, the SA Nationals are not as dominant in rural areas as their eastern state counterparts. Karlene Maywald was the MP for Chaffey from 1997 and the SA National Party parliamentary leader. She was re-elected at the 2002 and 2006 state elections (three other candidates were fielded in Flinders, Finniss, and MacKillop), announcing that she would support whichever party won government, which happened to be a landslide to the Australian Labor Party. Maywald became a minister in the first term of the Rann government. and signed an agreement with Mike Rann and the Australian Labor Party for reserving the right to not vote with the government, whilst at the same time becoming the Minister for the River Murray amongst other portfolios to the benefit of her constituency. Positions accepted were Minister for the River Murray, Minister for Regional Development, Minister for Small Business, and later Minister for Water Security. This informal ALP-NAT coalition (the first since 1935) caused uproar, with Christopher Pyne calling for Maywald's expulsion from the Nationals and Patrick Secker calling for a corruption enquiry into the appointment – neither eventuated.
The SA Nationals received a 6.6 percent primary vote at the 2009 Frome by-election and contributed to the election of independent Geoff Brock whom the party exchanged preferences with. At the 2014 South Australian state election, The Nationals polled well below 1% of the primary vote for both houses of parliament. Unlike their sister branches in New South Wales, Victoria and Western Australia, the South Australian Nationals are no longer a force of any real political significance in their state.