Next December, the European Union will have a special Summit meeting devoted to defence matters.

This is an important meeting because European countries have substantial mutual values and interests to defend, militarily and otherwise.

Europeans want to prevent genocide anywhere in the world. We remember what happened in Rwanda when the international community could not, or would not, act.

But we have more selfish interests too. Europeans import 50% of our energy, often from unstable parts of the world. We live by trade, so we need to keep vital trade routes open. We want to avoid huge uncontrolled flows of refugees into Europe from conflicts in our vicinity.

As a continent with 20% of the world income, but only 7% of its population, we want to uphold international law. 
Most EU member states are members of NATO, which is a military alliance and has capacity to deal with such questions. Some, like Ireland, maintain a policy of military neutrality. 
NATO is heavily, and perhaps unhealthily, dependent on the military strength and will of the United States. The United States share of NATO spending has risen from 63% in 2001 to 77% today. 
United States and European interests will not always be identical. The US will soon be self sufficient in energy, the EU is unlikely to be so in the foreseeable future. EU and US attitudes to international law are not always identical….for example on Guantanamo and drones.

Although the US pays the bulk of NATO’s bills, EU nations spend a great deal on defence. In fact they spend 200 billion euros a year, which is more than the defence spending of Russia, China and Japan combined!

But is EU defence spending as cost effective as that of, say, China?

There is a lot of duplication in defence spending by EU states, which is difficult to afford or justify, when other forms of spending are being cut back. EU states have 23 different types of armoured vehicle,4 different types of tank, and 7 different types of helicopter, which would make it more difficult for EU states to synchronise operations or  pool spare parts, if they did have to fight together in mutual defence, whether in a NATO context or otherwise.  
The European Union has an agreed security strategy. It was prepared for it by Javier Solana in 2003. It said that, for the EU, the 

”first line of defence will often be abroad”. 

But EU states lack the capacity to transport troops and equipment long distances, and have to rely on the Americans for this. This means that the EU is not the master of its own defence policy. At critical moments, the US is.
Among EU states, only The United Kingdom and France have significant military capacity. And these are the only EU states with seats on the UN Security Council. This gives them inordinate influence. 
For example, the EU recently lifted its  embargo on supplying arms to the parties in the Syrian civil war, a course demanded by France and the UK, who favour the rebels, although the other 25 EU states wanted to keep the embargo in place. On matters like this, where decisions are supposed to be unanimous, 2 states were still able to get their way over 25! 

We now have a strange situation in Syria where Britain, France, Saudi Arabia and Al Qaeda are on the same side. 
Already in Iraq, western intervention has released sectarian forces  that led to a decimation of the Christian minority in that country. The same is likely to happen in Syria, if the side favoured by France and Britain wins. 
One has to ask if this is compatible with either the values, or the security interests, of the European Union.

One also has to ask if the concept of European Union defence can have much reality, if decisions on it, are made by the same system by which the Syria arms decision was made. 
That said, EU military cooperation has had some notable successes.

For the EU, safe sea lanes are a vital interest. 90% of all EU trade travels by sea. A few years ago piracy off the coast of Somalia was a huge problem for EU ships coming out of the Red Sea into the Indian Ocean, a vital trade route for EU exports to Asia. Now, thanks to a combination of  EU naval action, and EU development aid to Somalia, piracy on this sea route has been cut by 95%.
The European Union has also had considerable success in brokering a peace deal between Serbia and Kosovo. It has been able to do this, partly because both countries would like eventually to be members of the European Union.
A neutral island nation like Ireland has strategic interests to look after too. It needs trade routes to remain open. It needs to be able to import energy. It needs peace in Europe if it is to prosper.

Defence costs money.

The decision Ireland has to make is whether its security can be achieved more cost effectively by greater pooling of resources on defence matters with other EU states, or by  acting independently. This is a discussion that should take place before the December EU Summit.