The inimitable Nick Xenophon was on form this week, just days after announcing his resignation from federal politics. Capital Hill’s most colourful parliamentarian was in California (where else would he be?) chasing sheep (what else would he be doing?) through the suburbs north of Los Angeles. But then Nick Xenophon has never been your run-of-the mill pollie.

He was staging a protest (using a flock of sheep) in support of Aussie Ugg boot manufacturer Eddie Oygur, who is locked in a David and Goliath struggle with US company Deckers. Deckers has claimed global rights to the Ugg name and is suing Oygur for millions of dollars, for alleged breach of trademark. But the American shoe giant hadn’t reckoned on locking horns wiith the South Australian senator. That he paid for his trip out of his own pocket speaks volumes about the man and his passion for standing up for the underdog.

“It’s about bringing back Ugg to Australia,” said the senator, “so Australian companies can make Ugg boots and export them to the world.”

Good on’im. Fighting the demonstrably good fight is what has endeared this unconventional politician to the Australian public, and swathes of South Australian voters over successive federal parliaments from 2008 onwards.

Fond of horseplay to get his message across, there always seems to be an animal around somewhere. Ten years ago Xenophon led a mule named Katie down Adelaide’s Rundle Mall – a metaphor for the stubbornness he’d bring to representing SA voters in Canberra. Later he called a press conference at Adelaide Zoo in front of the giraffes’ enclosure, (yes, you’ve got it), declaring he’d “stick his neck out for South Australia”.

But behind the puns and the slapstick, this is a politician deeply serious about the causes he fights for. Perhaps his volte-face last week shouldn’t have come as a shock; earlier this year he launched the SA-BEST political party with a promise to create a third option at the 2018 state election. “For the first time ever, in South Australia, there will be a genuine three-way contest,” he vowed in March, adding that he was putting “the out-of-touch political elites on notice that their age of entitlement is well and truly over.” It’s not an idle threat.

There’s little doubt that Xenophon’s move will create a sea-change in the state’s political environment. Already, the oracle, ABC analyst Antony Green has predicted SA Best will poll well-enough “to finish first or second in enough seats, to make it very unlikely either side can win a majority in its own right”.

With the slogan “Real change you can trust”, Xenophon’s return to lead the charge against Labor and the Libs is already having an effect, with Labor quick off the blocks to voice its ‘take’ on Xenophon’s move.

Federal Labor’s Steve Georganas has admitted Xenophon’s return is certain to make the next SA state election “interesting”.

“Nick has seen an opportunity in SA state politics with the current Marshall Liberal Opposition inept and void of policy and direction… he wants to fill that void,” said the Member for Hindmarsh.

While Labor has left open the possibility that it could do a deal with Xenophon in the case of not achieving a majority, SA Liberal leader Steven Marshall has been quick to rule such an arrangement out, saying voting for Xenophon could lead to Labor securing an unprecedented fifth consecutive term. But can the Libs afford to make such sweeping statements? The Turnbull government is proof that Xenophon’s centrist agenda is something a Liberal administration often has to live with, and benefits from. Steven Marshall may claim the people of South Australia “deserve a reformist government… and the only way to get that is to put the Liberals first”, but despite the Libs’ best efforts, SA-BEST are odds-on to be the king maker.

The South Australian State Election will take place on 17 March 2018 and Xenophon will contest the inner north-east Adelaide seat of Hartley. Currently held by the Liberal’s Vincent Tarzia (who just got past the post in 2014 with a slim majority over Labor), Xenophon will be one of up to 20 candidates to run under the SA-BEST banner. Watch out for the animals.