Global political considerations
Since 1688, Britain’s national interest has been advanced by ensuring there was a balance of power in Europe: making sure no nation or alliance dominated the continent and curtail Britain’s actions globally. Much blood and treasure have been spent in the pursuit of that foreign strategy objective and engagement in at least 12 Great Power continental and global conflicts , plus innumerable proxy conflicts. Since WW2 ( in which time there have been no great power conflicts for 70 years – longer than any time in modern history), it has been in Britain’s interests to pursue these goals via European cooperation and not through disengagement. The EU was established as a core vehicle for facilitating cooperation in several areas. Whilst Britain’s historical experience of devastating invasions and totalitarian government is fundamentally different to most European states (leading to claims we treat the EU “transactionally”), nonetheless it is in our interests to be influencing its development at its core, not in a detached manner. Past British leaders of European and Global coalitions [Marlborough, the Pitts, Wellington, Palmerston, Lloyd George, Churchill, even Thatcher] would surely be turning in their graves at the strategic failure of recent British leadership.
Once the EU became one of (not the only) bases of peace and economic power in Europe, it has clearly been in Britain’s national interest to be in and remain in it so no nation or alliance dominated the continent. If we were outside or marginalised in the EU we would not be able to influence the power structures of the continent which would be to our longer term national disadvantage. If as many BrExiters claim “our parents and grandparents didn’t fight two world wars to allow Germany to dominate Europe”, then leaving the EU would, in fact, allow Germany to dominate the EU without a shot being fired [though most sane people would agree that a continent “dominated” by a peaceful, democratic Germany is far preferable to one dominated by either the Kaiser’s Germany or Hitler’s and it is hyperbole to compare Germany today with either. Nonetheless the EU as a Nazi grand plan has gained some currency in Europhobic circles.]! The primary reason for BrExit would seem to be that it’s tiresome and frustrating negotiating with other countries: why can’t they let us get our way rather than having to do all this interminable horse trading? Apparently outside the EU, in international forums with many more members it’ll become a lot easier!
Bear in mind that ANY international treaty makes concessions on national sovereignty: as UN members we have constraints on our ability to wage wars [surely the greatest manifestation of a truly sovereign state], how we treat refugees and what rights we afford our citizens (further codified in the ECHR of which the UK was a founding member); as NATO members we have commitments to wage war against aggressors towards other members whether we are threatened or not [and most recently in determining the amount of GDP we spend on Defence]; as members of WTO we have constraints on trading practices; as CERN and ESA members we have obligations to collaborate with other states in the conduct of “big science”. Increasingly we must adhere to global agreements on pollution: No nation can pollute its neighbours without consequences. Name any treaty signed by the UK that is still in force and any international organisation we are members of and I can show you “outrageous” infringements of our national sovereignty, in return for benefits that are intended to outweigh those infringements. The logical destination of those arguing we must leave the EU to “restore our national sovereignty” is we must leave the UN, NATO, WTO, CERN, ESA etc and abrogate every international treaty we have, turning us into a rogue state.
In fact, of all these constraints on our national sovereignty, only the EU received a mandate from the electorate via a referendum. And that referendum was more than about trade: I voted and the goal of “ever closer union” was clearly part of the deal we voted for, despite Eurosceptic mythology that we were deceived ever since.
In the 21st Century there are a huge range of problems that cannot be dealt with unilaterally but by collaboration with other nations and geographies. The EU provides a regional bloc of free trading liberal democracies to address problems such as climate change (and let’s face it it really is not coincidental that so many Eurosceptics are also climate change deniers), terrorism, trade, security, crime, refugees, etc etc. never mind whether we are potentially a few quid a week better or worse off in or out, if we don’t solve these problems properly and sustainably it really won’t make much difference. That requires sovereignty pooling to collaborate.
 The War of the Grand Alliance; the War of Spanish Succession; Great Northern War; the War of Austrian Succession; the Seven Years War; the War of American Independence; the French Revolutionary War; the Napoleonic Wars [several distinct phases]; the Greek Revolutionary Wars; the Crimean War; The First World War; Russian Civil War; the Second World War.
 Both my parents fought in WW2. Neither made that sacrifice nor saw friends and relatives make sacrifices to bring about the narrow minded, mean spirited, isolationist type of Britain that many in UKIP and the Europhobes advocate. Whilst it is true that they did not wish to see Britain “ruled” by Europe, it is a grotesque mis-characterisation of the EU to suggest that it rules any of its members.
Below is a more detailed exploration of the issues: