(Bloomberg) — Childcare worker Amy O’Neill thinks the old ways of Irish politics may have run their course.The 26-year old from Tipperary works two jobs to make ends meet and usually votes for Fine Gael, one of the two parties that have largely dominated Ireland’s political landscape since the foundation of the state a century ago. As she prepares to vote in Saturday’s election, she’s considering making a change.“I’m leaning toward Sinn Fein,” said O’Neill.She’s not the only one. The left-wing nationalist party, once the political wing of the IRA terrorist group, jumped into the lead in one poll in the final days of campaigning.The electoral math of a fragmented system means Sinn Fein won’t lead the next government, but its rise speaks to the shifting tectonic plates that are upending traditional power structures in Ireland and across Europe.When O’Neill joined an estimated 20,000 childcare workers marching through Dublin on Feb. 5 to demand better pay and conditions, the buzz was all about a shift to the left.“That’s what everyone here is talking about,” she said.Voting began on some of Ireland’s islands on Friday, with the mainland going to the polls on Saturday. State broadcaster RTE will release an exit poll immediately after voting ends at 10 p.m. tomorrow. Around Sunday lunchtime, it will become clear if the centrist hold on power has been broken. The traditional divide in Irish politics runs between Prime Minister Leo Varadkar’s Fine Gael and Fianna Fail, separated by little except where they stood on the division of Ireland in 1921.In 1982, the two dominant tribes accounted for 84% of the vote. By 2016, they had less than 50% of the vote and that’s likely to fall further tomorrow as Sinn Fein makes inroads.The shift in Ireland matches a pattern that has seen traditional parties eroded in places like Germany, Italy and Spain — and all but wiped out in France where President Emmanuel Macron and the right-wing populist Marine Le Pen overturned the old guard in 2017.In Ireland, Sinn Fein can’t lead the next government because it isn’t running enough candidates to clinch a majority. But Fianna Fail’s Micheal Martin, the favorite to take power, may face an awkward dilemma: does he bring Sinn Fein into his coalition or allow them to become the main opposition?He’s officially ruled out a pact, though the bookmakers still make it the most likely outcome. Either way, Sinn Fein’s influence is set to grow.“There is something important going on here,” said Eoin O’Malley, a politics professor at Dublin City University. “After almost 100 years, voters are becoming sick of the two big parties, Fianna Fail and Fine Gael and are looking for change.”He said Sinn Fein could be in a position to take power itself come the next election.Before then, Sinn Fein leader Mary Lou McDonald may force the next government to do more to protect workers rights and boost wages. She’s promised people like O’Neill she would spend an extra 500 million euros ($550 million) on childcare providers, raise entry-level wages and make the state responsible for pay and pensions in the sector.Irish voters may be open to a more regulated economy after both the main parties ran into trouble for their handling of the state finances — Fianna Fail is struggling to shake off its role in Ireland’s 2008 economic crash while Varadkar has overseen vast cost overruns on projects like the new National Children’s Hospital.Nevertheless, Varadkar and Martin both attacked her tax-and-spend plans during an election debate last month.“Listening to these men you’d never imagine that one had crashed the economy and that the other is so fiscally irresponsible that he’s producing the most expensive hospital in the world,” McDonald replied.The Irish BorderSinn Fein’s main historical mission has been to reunite the two parts of the island of Ireland and the deal that Varadkar struck last year over the border with Northern Ireland has already weakened the ties binding the six Irish provinces to the rest of the U.K.Brexit has also helped soften opposition to reunification in the north and Sinn Fein, the only group with a significant representation in institutions on both sides of the border, could increase the chances of a vote on the issue.The party only began seriously contesting Irish elections in the 1980s under a strategy known as “the Armalite and the Ballot Box” — in which the Republican movement sought to further its goals through both democratic means and violence.The end of the Troubles in 1998 helped to normalize the party, but it’s still never been in government. And in an election where voters are demanding change, that’s a significant advantage.Sinn Fein may be tapping into “a latent republican sentiment, also fueled by the long Brexit saga,” said Diarmaid Ferriter, professor of history at University College Dublin. But mainly, he added, the party is “a lightning rod for the discontent out there, for the things that people feel are wrong about their lives.”(Adds election details in seventh paragraph)–With assistance from Ben Sills, Peter Flanagan and Rachel McGovern.To contact the reporter on this story: Dara Doyle in Dublin at ddoyle1@bloomberg.netTo contact the editors responsible for this story: Chad Thomas at cthomas16@bloomberg.net, Ben SillsFor more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.