DUBLIN (Reuters) - A campaign to inject German-inspired budget discipline into the Irish constitution is proving painful for the centre-left party propping up the government, alienating parts of its working-class base and boosting the rise of a populist rival.
The Labour Party stormed into government last February for the first time in 14 years on a promise to end the previous government's adherence to "Frankfurt's Way," an austerity plan the party said was dictated by the European Central Bank.
But the three-month run-up to a referendum on the EU fiscal treaty, after the coalition has spent a year implementing the terms of that same programme, has highlighted Labour's deference to Europe while left-wing rival Sinn Fein leads the opposition.
While opinion polls show that Labour and other supporters of the treaty are likely to prevail in Thursday's vote, the campaign has proved far more uncomfortable for Labour than for its partner, Prime Minister Enda Kenny's Fine Gael.
"The referendum has put Labour in a bad place and allowed the populist vote to go to Sinn Fein," said Neil Collins, a professor of politics at University College Cork, noting that minority government parties often suffer in Irish politics.
"It will be very difficult for them to bounce back."
A poll this week showed Labour's support had almost halved from 19 percent in the election to 10 percent, while that of Sinn Fein, buoyed by its opposition to the fiscal treaty, has more than doubled to 24 percent from 10 in the election.
Twice as many Labour voters, who have traditionally been sceptical of European treaties, plan to vote against their party's position in Thursday's referendum as supporters of coalition partner Fine Gael, polls have also showed.
Labour has traditionally had two sources of support: the working class socialists and heavily unionised middle-class state workers. The crisis that drove Ireland to seek an EU/IMF bailout 18 months ago is driving a wedge between them.
Middle-class workers, including state workers protected from forced lay-offs by a union deal, are keener to maintain the status quo and polls show they are more likely to vote "Yes."
Swing voters in working-class areas who are struggling to deal with a raft of new taxes and cuts to state services are becoming increasingly angry that austerity is not being spread.
Opinion polls show they are more likely to rebuff Labour's advice and vote "No", in a possible preview of where they will stand in 2016, when the party will still be doling out painful medicine as parliamentary elections are held.
"It's a very difficult campaign and it's a difficult thing to win because people are blinded by the pain," said Labour member of parliament Eric Byrne, campaigning close to a bingo hall in the working-class Dublin suburb of Crumlin last week.
While most of the people he spoke to were ready to vote yes, there was clear anger that austerity was not being spread evenly.
"There's no pain for the right people," said Barbara Kelly, a 41-year-old pre-school teacher and mother of two. "We can't take any more austerity."
"So unless you can stand here and tell me now that the people that are going to be hit with austerity are going to be the higher middle-class earners, well I'm not going to go with it and I'm going to take my chance and throw my money to the wind (voting no)," she said.
While Labour may be able to weather the anger of some of its voters disappointed by broken promises, the loss of its working-class roots could be extremely damaging in both the short and long term.
"The problem for Labour is losing what would have been its old core (working-class) constituency," said Richard Sinnott, a politics professor at University College Dublin.
"For Labour to win those voters back and not become kind of a niche middle-class party is going to be very difficult."
Editing by Padraic Halpin and Tim Pearce