These are the terms in which Gordon Brown explained his vision for the future of the UK in his rather good book, My Scotland, Our Britain: A Future Worth Sharing (2014). The rationale for the Union, according to Brown, is to be found in the common advantages that all Britons enjoy from having an integrated economy, from the pooling of risks, and from the transfer of resources from richer to poorer across the whole territory of the UK. That’s why it’s vital that the Westminster government continues to insist upon retaining control over such things as national insurance and the state pension, and to refuse the Scottish nationalists’ reckless, dogmatic demands for full fiscal autonomy. It’s vital for the well-being of all the British peoples, not least the Scots themselves.

Stronger external security and common economic advantage are two things that the Union is good for. A third is the habit of taking responsibility for upholding a liberal and humane global order, if necessary by deploying hard power. This, of course, is the legacy of empire and manifests itself in Britain’s retaining a place among the permanent members of the UN Security Council.

Scottish nationalists typically despise this, seeing Scotland’s becoming independent, dissolving the United Kingdom, and adopting a more “Nordic” role in international affairs as an act of repentance from Britain’s immoral tradition of imperial aggression and domination. They regard the British policy elite’s hankering after the imperial power and role of global policeman, albeit now with the reduced status of deputy to the US’s sheriff, as at once delusory, pathetic and immoral. It’s delusory, because Britain no longer has the power to rule the world as she once did. It’s pathetic because it makes the British play poodle to America. And it’s immoral, because it involves threatening and dominating other peoples, often by waging war against them, sometimes in violation of international law. Instead, they argue, the UK should shake off its post-imperial hangover, follow Europe rather than America, surrender its nuclear weapons, concentrate on wielding soft power, and limit its military activity to UN peacekeeping operations. And if the UK will not choose to do that, then Scotland will force her — by breaking the Union.

There are several grounds on which to refuse this notion. First, the history of the British Empire was not one of relentless aggression and oppression. Yes, it presided over the infamous massacre at Amritsar in 1919 and the outrages of the Black and Tans in Ireland in 1920-22, but it also pioneered the suppression of the slave trade in the 19th century and was the only opponent of European fascism in the field from May 1940 until June 1941. The present fact of the Commonwealth is evidence that the empire’s historical record is not simply execrable. Rather, it is morally mixed — as is the record of any nation-state.

Second, it simply isn’t true that post-war Britain has always meekly trotted along behind the US. Harold Wilson refused to send British troops to Vietnam; Margaret Thatcher arm-twisted Ronald Reagan into supporting the ejection of the Argentines from the Falkland Islands in 1982; and Tony Blair publicly embarrassed a very reluctant (and resentful) Bill Clinton into deploying US military force in Kosovo and Serbia in 1999.