The Irish government last week set a date in October for a second referendum that could make or break the European Union's plans to admit more nations and forge a larger united Europe.
Irish voters surprised Europe last year when they rejected the Nice Treaty, a package of reforms to prepare the EU for enlargement, and a second defeat would kill off the accord.
Prime Minister Bertie Ahern and his Cabinet set the vote date for Oct. 19, just days before EU leaders meet in Brussels. It is the first time the Irish will hold a national vote on a Saturday, chosen to encourage as big a turnout as possible.
Ireland is the only one of the 15 EU member states where the treaty, named after the French city where it was hammered out in December 2000, must go to a referendum to be ratified.
Many here fear enlargement will trigger a rush of Eastern European immigrants and compromise Ireland's jealously guarded tradition of neutrality in military matters.
The European Commission in Brussels has given grim warnings about the consequences of a "no" vote, but a spokesman refused to be drawn into painting a do-or-die scenario.
"The commission takes note of this date, which will be an important date for the future of Europe," a spokesman for Commission President Romano Prodi said. "It's now up to the Irish people to decide."
A second "no" vote would kill the treaty, which must be adopted by all 15 countries, and could jeopardize the plan to bring in 10 more members from the former Soviet bloc and the Mediterranean.
To try to reverse last year's vote, in which only 35 percent of the electorate turned out, Ahern has promised the biggest referendum campaign since Ireland joined what was then the European Economic Community in 1972.
He has urged members of his Fianna Fail party to campaign as if it were a general election, saying the treaty was politically and economically "vital" to the country.
A "yes" vote would be a prize for Ahern to take to his fellow EU heads of state and government when they meet Oct. 24-25 in Brussels.
Deputy Prime Minister Mary Harney of the Progressive Democrat Party said it would be a "crucial" vote for Ireland and for the EU.
Opinion polls have shown widespread confusion and ignorance about the complicated treaty, which amends the Treaty of Rome - the EU's cornerstone - to streamline decision-making once the bloc gets bigger.
A state-funded referendum commission, charged with explaining the issues and encouraging people to vote, said last week its research found only 16 percent of people "adequately" understood the treaty.
Only 28 percent of people under 24 said they would definitely vote, according to the research.
A new alliance of Nice opponents was announced Sept. 19 including the environmental Greens, Sinn Fein, the Socialist Party, the Socialist Workers Party, the Workers Party and independent left-wing MPs.
A poll of 400 farmers published by the Irish Farmers' Journal newspaper meanwhile showed the "yes" vote had dropped from 47 percent to 45 percent. It indicated the number of farmers planning to vote "no" had increased by eight points to 27 percent.
Ireland's farmers have done well from EU membership. But there is concern about agricultural policy reforms and the impact of new Eastern European applicant countries with large numbers of small farmers.