TODAY the commentariat, and almost no one else, has been waiting excitedly for Boris Johnson to show his colours in Britain’s upcoming EU referendum. The great moment came at 3:30pm with the BBC’s confirmation of prior reports that London’s mayor would back a Brexit vote. This news is bad for the In campaign—he is the country’s most popular politician, after all—though not nearly as much as some excited Eurosceptics will claim in the coming hours. It positions Mr Johnson to run for the Conservative leadership should David Cameron lose the referendum, and perhaps, though not as immediately, if he does not. But shamelessly self-interested and probably contrary to his real views on the EU though it is, the mayor’s move is perhaps not entirely disingenuous. He has always insisted that his decision would turn on his concerns that EU membership is incompatible with British sovereignty. Expect him to concentrate on this objection in the coming days.



Mr Johnson has thus aligned himself squarely with Michael Gove, the justice secretary with whom he consorted earlier in the week and who declared his support for Brexit on Friday in a 1,500-word statement that overwhelmingly concentrated on national self-rule. The "decisions which govern all our lives", Mr Gove argued, should be taken uniquely by "people we choose and who we can throw out if we want change". It is worth taking this variety of Euroscepticism seriously—partly because it comes from the more thoughtful, liberal wing of the movement (Mr Gove is not the Little Englander of Europhile lore, for example). But also because it will feature very prominently in the debates between now and June 23rd, especially as Mr Johnson will now presumably become the face of the Out campaign.



The Johnson-Gove argument goes something like this: unlike many continental countries, Britain has an unbroken tradition of liberty and representative democracy (a "golden thread") dating back to Magna Carta and shared by other Anglophone nations. This tradition is almost uniquely uncompromising about accountability, steadfast in the conviction that power should rest only in the hands of leaders elected by and answerable to a nation constituting a demos, a community of shared assumptions and experiences. Thus the EU, accountable to foreigners as well as Britons, breaks the sacred bond of mutual power between decisionmakers and those on whose behalf they act.



The flaw in this case lies in the tradition's idealistic definition of sovereignty. For Mr Johnson and Mr Gove, being sovereign is like being pregnant—you either are or you aren’t. Yet increasingly in today’s post-Westphalian world, real sovereignty is relative. A country that refuses outright to pool authority is one that has no control over the pollution drifting over its borders, the standards of financial regulation affecting its economy, the consumer and trade norms to which its exporters and importers are bound, the cleanliness of its seas and the security and economic crises propelling shock waves—migration, terrorism, market volatility—deep into domestic life. To live with globalisation is to acknowledge that many laws (both those devised by governments and those which bubble up at no one’s behest) are international beasts whether we like it or not. If sovereignty is the absence of mutual interference, the most sovereign country in the world is North Korea.



Thus the EU is just one of thousands of intrusions on the sort of sovereignty that the likes of Mr Johnson so cherish. Britain is subject to some 700 international treaties involving multi-lateral submissions to multilateral compromises. Its membership of the UN similarly infringes its self-determination, for it can be outvoted there just as it can in Brussels. Likewise the WTO, NATO, the COP climate talks, the IMF, the World Bank, nuclear test ban treaties and accords on energy, water, maritime law and air traffic all require Britain to tolerate the sort of trade-offs that Eurosceptic souverainistes find distasteful: influence in exchange for irksome standardisation, laws and rules set mostly by foreigners not elected by Britons (regulations that Britain would not apply, or would apply differently, if left to its own devices). Yet it submits to all of these knowing that, as with the EU, it is free to leave whenever it wants—but at a price not worth paying.



This is precisely why the two models for a Britain outside the EU often cited by Eurosceptics (including Mr Johnson), Norway and Switzerland, constitute such weak arguments for Brexit. Under the Johnson-Gove view, these countries are quite dramatically more "sovereign" than Britain. But in practice their economies and societies are so intertwined with those of their neighbours that they must subject themselves to rules over which they have no say. This exposes a false choice: in an increasingly interdependent world, countries must often opt not between pure sovereignty and the pooled sort, but—however distasteful the choice may seem—between the pooled sort and none.



Perhaps the very reason why this seems distasteful needs revising. The premise put forth by the souverainistes is that Britain, unlike the EU as a whole, is a coherent demos: a discrete civic unit with a distinct sense of right and wrong, a shared corpus of civil assumptions and most of all a common dialectical realm (as Benedict Anderson noted, the rise of nationalism in the 19th century was associated with emergence of a mass media, making the "imagined community" of nationhood possible). In other words the British electorate can, in its collective wisdom, reach judgments about politicians and policies in a way impossible among the EU population as a whole, with its 24 languages, 28 national media landscapes, multiple legal systems and vast range of historical and ideological hinterlands. Hence, not without reason, the Eurosceptic offence taken at comparisons of the democratic legitimacy conferred by European Parliament to that conferred by national parliaments.



Much of this holds true. But to what extent? The media is fragmenting and internationalising. The citizens of a given country do not all watch the same television programmes and read the same newspapers any more. Across Europe there is evidence of growing political polarisation along cultural lines: for all their differences in experience and outlook, voters in declining, post-industrial parts of England and France have much more in common with each other than with those in cosmopolitan London or Paris. Language divides people less all the time. Sub-national allegiances are growing in strength (note Scotland’s slide towards independence) and form an increasingly appropriate and effective basis for government (consider all the recent literature on the "age of mayors"). So while one can still argue that power exercised at a national level is more democratically valid than that exercised at a supra-national one, that case becomes less pressing with each passing year.



A final observation. Talk of foreigners imposing their will on Britain’s elected government is usually (and especially in Mr Johnson’s case) accompanied by a patriotic flourish: the assertion that, as one of world’s great economic, cultural and military powers, the country deserves to get its autonomy back and can make it on its own. But this chest-puffing diverges from the underlying sovereignty argument, which only works if, deep down, you think Britain a bit puny. Consider the trade-off: let foreigners have some influence over your country of 64m and in return receive quite a lot of influence over a union of more than 500m. When Eurosceptics only mention the first half of this bargain, they imply that Britain is too weedy to take advantage of the second. Which is odd, as the national strengths they otherwise celebrate give the country a tremendous ability to do so. Its diplomatic service, its global alliances, its language, its historical heft—not to mention the absence of a power similarly well positioned to exercise continental leadership—all put it in a fantastic position to set the agenda in Brussels at those rare moments (for example, at the time of the Lisbon Agenda and the union’s eastwards expansion) when it puts its mind to the task. The EU is Britain’s to run, if only it could overcome its insecurity about scary foreign bullies. In an interconnected and ineluctably integrated 21st century, it is that, far more than the Eurosceptics’ purity games, that is real sovereignty.

Correction: The original version of this story suggested that the population of the European Union was 743m. This has been corrected.