A  "yes" vote in Friday’s referendum on the Lisbon Treaty, or “neverendum” as some wags are calling it, is vital for Ireland.

A no vote will send a clear message that Ireland wants it both ways -- the benefits of European Union membership without any of the obligations that that membership implies.

The last time the Lisbon Treaty came up for vote in Ireland, the country said no. This time the Irish have received additional assurances from EU leaders that their concerns have been met. There is simply no excuse to vote no again.

There are clear implications in America for a no vote if that is successful. None of those implications are positive.

After the last no vote the industrial development authorities in several other countries that compete with Ireland’s IDA made it clear to leading American businessmen that Ireland was no longer a fully-fledged member of the EU.

While that was certainly stretching the truth, it nonetheless had an impact, with the Irish IDA forced to defend its turf and make clear that all the benefits of EU membership still applied to potential businesses locating there.

Foreign investment remains the engine of the Irish economy, and a no vote on Europe could have a significant adverse impact on that. Several leading American businessmen have already made that clear in the Irish media.

In the current economic climate, the last thing that Ireland Inc. needs is confusion on this side of the Atlantic on whether it is a fully paid up member of the EU, the institution that has been the springboard for rapid economic investment in Ireland in the modern era.

On another level, Ireland needs to play its part as full partners in the EU expansion which is planned for the future.

As a small island of the western seaboard of Europe, institutions like the EU and the United Nations provide Ireland with powerful platforms on an equal basis that they would otherwise not enjoy.

Like the Irish diaspora, the EU and UN are vehicles where Ireland’s footprint on the world stage can be vastly enlarged over what it is now. To throw away that benefit of EU membership for no good reason would be damaging to say the least.

Opponents of the treaty say that a European super state is being built and that Ireland will only be a tiny cog in it, and will also have to concede sovereignty.

The reality is that some sovereignty has been conceded, but nothing that would make any except the most partisan nationalists worry about the long-term impact.

The isolation of a country like Iceland in the recent financial crisis when its currency effectively collapsed is a frightening reminder of what could have happened to Ireland if it wasn’t a part of the EU and had the single currency to buffer its collapse.

That example alone should be enough to make the Irish electorate aware of how important their vote is on this Friday. A no vote would be disastrous for all concerned.

A yes vote, however, allows the country to continue its voice in Europe and keep a level playing field against competitors for American foreign investment here in the U.S.