Arguably, Nations need to be defended, otherwise they are at risk of invasion. So, a decision as to whether to have armed forces needs to be made, and policies worked out as to their deployment and use. Where should these forces recruit – does the Nation need them to be used to control local situations? What about international issues? Every significant nation has an Army, a Navy and an Air Force, in order to have some form of influence and to protect its national interests. Of course, some nations are wealthier than others and so can afford larger, more competent forces. But decisions of investment need to be made so that the balance of force is proportionate to the status and the wealth of the nation.
Arguably, it’s not enough simply to be able to afford arms, Technology will always advance and threats to national security will change. So, nations need to be knowledgeable about their options and about the capabilities of those who might wish to oppose them. It might be necessary to have an arms industry, of it might be sufficient to depend upon the expertise of other friendly nations who may be prepared to share their technology. It seems that it pay to know who your friends really are. seriously.
There are, according to Wikipedia, some twenty-one sovereign states that have no official military forces. Five others have no standing army but limited military forces. The remainder, some (195 states worldwide) hundred and sixty nine, do have, and these may have interdependence – it’s estimated that between 1815 to 2003 there have been 538 alliance treaties. The most significant seems to be NATO, with 32 members, but of course this excludes superpowers such as China and Russia. In contrast, it’s estimated that there are between dozens and over 130 armed conflicts ongoing, worldwide. Life doesn’t seem to get simpler.
So, probably, we do need armed forces, and here in the UK the Navy has existed since 1546, the Army since 1660, and the Air Force since 1918. It doesn’t seem that any will be disbanded. Our government needs to decide upon their use, their funding and what their priorities should be.