(DUBLIN) - Ireland's fierce protection of its military neutrality is emerging as a key battleground ahead of a crunch referendum on a controversial new EU treaty.

The country's 26 European Union partners are watching closely as campaigning gears up ahead of the Irish poll on the so-called Lisbon treaty, expected in May or June.

Irish voters already sent shockwaves across Europe in 2001 when they rejected the Nice Treaty, with the neutrality issue a key weapons for opponent who warned that Dublin would lose its military sovereignty.

All such treaties have to be ratified by all EU states to come into force -- the Nice pact was eventually passed after Ireland embarrassingly organised and won a second referendum.

But that victory was only secured after Irish premier Bertie Ahern persuaded his EU counterparts to sign a declaration guaranteeing Ireland's military neutrality at a summit in Seville, Spain in 2002.

The Irish Republic is proud never to have gone to war -- even if its army regularly takes part in peacekeeping missions, with 400 heading off next month to Chad as part of an EU force which has an Irish commander.

Pacifism is deeply ingrained in the Irish spirit.

"It would be a very worrying scenario if a decision of a military action were taken without Ireland," said senator Deirdre de Burca of the Greens, in the Yes camp for the treaty.

The Lisbon Treaty, signed amid much fanfare in the Portuguese capital in December, requires unanimity for any EU decision on foreign policy, in particular over sending troops.

But a qualified majority is enough to agree the enactment of a decision already agreed unanimously -- and it is this subtle distinction that has some Irish people worried.

"Ireland could be opposed to a war and could have no say in a vote," said Carol Fox of the Peace and Neutrality Alliance" (PANA), which will campaign against the new EU treaty.

The No camp puts the spotlight in particular on a Solidarity Clause in the Lisbon text, which allows for a military intervention to prevent a terrorist attack on EU territory.

For critics, this raises the nightmare scenario of Ireland being forced into battle in the Middle East to prevent an attack on another country, including its former colonial neighbour Britain, already a terrorist target.

Such fears have been fueled by speculation that former British premier Tony Blair could become the first holder of a new post of EU president agreed under the Lisbon treaty.

"Tony Blair could be the head of Europe and we would be in Iraq," said Joe Higgins, leader of the Socialist Party, which is campaigning against the treaty.

Those in the Yes camp however say accuse opponents of Lisbon of exploiting people's fears for their own cause.

"It's nonsense," European Affairs minister Dick Roche told AFP. Ireland already had two "belts and braces" guarantees against its neutrality being violated, he stressed.

Firstly, Ireland's constitution demands that any military engagement must be subject to a referendum. Secondly there is a "Triple Lock" mechanism whereby an deployment must be backed by the government, lawmakers and the United Nations.

Eamon Gilmore, head of the Irish Labour Party, insisted: "nothing in the Treaty provides for ... Ireland being forced into wars or imperialist adventures. Ireland's history of peacekeeping will be monitored."

On the contrary, said European Parliament lawmaker John Cushnahan, the Lisbon treaty would bolster Europe's political and military weight.

"We'll have a more common foreign policy, and we'll be able to counter-balance big powers like the United States," added Cushnahan, a member of Ireland's opposition Fine Gael party.

Text and Picture Copyright 2008 AFP. All other Copyright 2008 EUbusiness Ltd. All rights reserved. This material is intended solely for personal use. Any other reproduction, publication or redistribution of this material without the written agreement of the copyright owner is strictly forbidden and any breach of copyright will be considered actionable.