Some opponents of the Lisbon Treaty say a 'No' vote will have no consequences for our country and that it is an outrage to suggest otherwise. It is true that there will be no legal consequences: Ireland will not be expelled from the present European Union, nor is there any legal mechanism to sanction or disadvantage us, nor will we be drummed into a second tier of membership below our present legal status.
But the real -- as opposed to the judicial -- consequences of a second 'No' vote will be inevitable, devastating and irreversible for our political independence and for our prosperity.
Strangely, the reasons for this have been ignored so far in the debate, perhaps because in the din of the hundreds of secondary details we are all -- or many of us are -- ignoring the wood for the trees.
It is very simply that if we vote 'No' on October 2, the British will -- because of our vote, and only because of our vote -- withdraw from the Lisbon project (which their parliament has already ratified), while most of the other 25 member states will follow the lead of France and Germany and press ahead with another version of the Lisbon Treaty, creating a new and dynamic level of the European Union.
We and Britain and a tiny number of smaller member states will leave ourselves outside, just as Britain left itself outside the euro (which Ireland, thank God, joined).
Why should this be so? Almost every commentator expects that the next British government will be led by the Conservative Party. William Hague, their spokesman on foreign affairs, wants the Irish to vote 'No'. More important was his commitment of July 26 last year: "If Lisbon remains unratified by all EU states, a Conservative government will put Britain's ratification of the treaty on ice and hold a referendum, recommending a 'No' vote".
This means that a British referendum will happen only if Ireland votes 'No' on October 2. There will be a British general election next year: it is utterly inconceivable that the Labour Party, struggling to survive, would not match the Conservatives' campaign commitment to hold a referendum in the circumstance that Ireland had again voted 'No'.
And we all know, even though it's strictly none of our business, that in a post-election referendum a majority of the British people, never enthusiastic about the European Union, would themselves vote 'No'.
Conversely, this means that if we vote 'Yes' on October 2, Britain, which has already ratified Lisbon, will stay in the core (ie, Lisbon Treaty) EU. This will be the case whether under the Conservatives or Labour. So, of course, will our country, north and south. And so will the other 25 member states.
But, equally inevitably, if we Irish vote 'No', both Britain and Ireland will be outside the core project of Europe, which most (probably not all) of the other 25 member states will continue to push forward, led forcefully by France and Germany.
The most discouraging strategic problem for Irish nationalists for generations will then confront us: a tiny group of mainly smaller countries and one larger country, Britain, will every day have to negotiate a raft of vital issues with the new core EU submissively "from the outside" and, whether we like it or not, the core EU, a global power centre, will deal on these matters, not with Ireland, but overwhelmingly through Britain.
It would be agreeable to think that the power systems of the world worked in a more benign way with smaller countries who exclude themselves from the power system they formerly belonged to, but alas that is not the case.
If we vote 'No' we will find ourselves back where the colonial-minded among the British (have no illusions: they still exist in powerful roles and numbers) always wanted us: in the pre-1973 cauldron of Anglo-Irish claustrophobia and dependence.
It was Ireland's common and equal membership of the wider EU that eliminated our dependent status with Britain. Without it there would have been no serious Anglo-Irish negotiations on the North, no Anglo-Irish Agreement, no Good Friday Accord.
What is more, the Irish, once inside the EU, proved (much more than our neighbours), whether as farmers, trade unionists, employers, civil servants, volunteers or, yes, even as politicians, to be masters of the community's decision-making processes, gaining us respect, economic advantage and real independence and real sovereignty vis-a-vis Britain such as we had never previously enjoyed.
Anyone who suggests we weren't -- and aren't -- brilliant at fighting our corner INSIDE the processes of the EU is either completely ignorant or simply hostile to Ireland's membership (in itself of course a perfectly respectable position so long as it is honestly declared). One example should suffice: is it pure coincidence that the former and present secretaries-general of the Commission, the most powerful post in the community civil service, are Irish?
For me, a former civil servant both of the Irish government and of the European Commission, this is of all the Lisbon issues the most serious: let's keep and grow our independence of Britain by keeping both countries at the core of Europe.
A second vote against Lisbon would be a vote of no confidence in ourselves. It would also be, whether consciously or otherwise, a vote to return to the days of submissive dependence on Britain, with all that that entailed, as in the Ireland of the 1950s, in terms of humiliation, poverty, emigration and authoritarian hopelessness.
It would be throwing away the freedom we have won since 1973, the first real freedom we have enjoyed since independence.
Michael Lillis is a former deputy secretary of the Department of Foreign Affairs. He was a member of the team that negotiated the Anglo-Irish Agreement in 1985. He has also worked as an EU civil servant.