THE late Richard Kinsey, criminologist and stalwart for human rights, had a neat gambit when pub talk turned to constitutions.

The finest document ever committed to paper, Kinsey would say, appeared in the world in 1936. No country could have asked for more.

There were just two snags. The country in question was the USSR and the esteemed comrade chairing the drafting committee, always in the people's name, was one Joseph Stalin.

Kinsey was (wickedly) correct, for all that. As though to mock bloody realities, the 1936 Soviet constitution reads like a parody of noble intent. Universal direct suffrage, the right to work, rights to health and leisure, rights to housing, schooling, "culture", care in old age and illness: in terms of economic rights, above all, it promised more than any Western state had ever offered. And Stalin remained Stalin.

You could contrast and compare. The constitution of the United States is reckoned by Americans as another fine document. "We the People": for democrats, there's alpha and omega. "A more perfect Union"; justice, tranquillity, welfare, "the blessings of Liberty" - as a statement of national purpose, the preamble has all you could hope for.

If you believe some of its avid readers, though, a 1791 amendment to that marvellous document, since extended by the Supreme Court, enshrines the rights of every gun nut in the republic, with familiar results. Whether the men in powdered wigs had teenage shooting sprees in mind when they worried about overweening governments is a question over which Americans argue still. The lesson is plain enough: constitutions can have unintended consequences.

Nevertheless, an independent Scotland will need its piece of paper. There is no serious argument over that. For us, a sovereign democracy, least of all one deriving legitimacy from "the people", is in practical terms new. Old ideas of authority and the Thrie Estaites might be a nice rebuttal to Westminster doctrine, but the true common will, mobs aside, never did carry much weight. After independence, we would be starting from scratch.

In drafting its Scottish ­Independence Bill, the SNP ­Government has clung, for all that, to the assertion that "in Scotland, the people are sovereign". Why not? Arguments over history aside, where else would you begin in the modern world? If a constitution asserts a collective belief in a national community, if it seeks to give voice to a society's understanding of itself, its hopes and its ideas of legitimacy, there are no fit alternatives to "the people".

But if that is the case, why would the SNP also claim that a Windsor monarch should - must? - continue as head of state? The contradiction is glaring, especially when the bill, "skeletal" or not, seems to leave the royal figurehead with the power to withhold assent from legislation. Since when would a sovereign people accept such a thing?

That might depend who was asking - or, more particularly, who was drafting the constitution.

Andrew Tickell, the ­constitutional lawyer who blogs as Lallands Peat Worrier, was asking pertinent questions last week about the revered notion of "the people", and asking more particularly about how they can be represented in the making of a constitution. The SNP government has a constitutional convention and a "consultation" in mind. So how, if popular sovereignty matters so much, would those work?

Tickell points out that America got its liberties thanks to a small group of prosperous white men. The basic law of the Irish Republic was assessed more recently by a body split one-third to two-thirds between elected politicians and "ordinary" citizens picked, it was said, at random. Iceland has tried, with limited success, to remake its constitution with 25 specially elected folk and a "crowd-sourced" process. None sounds like the perfect expression of the popular will.

You could say the same, I think, about most consultations. They sound fine and well. Properly conducted, they can be a distinct improvement on the usual behaviour of the mandarin class. But much depends on what is "put out for consultation", and much more on what politicians choose to do with the results. There is no such thing as a binding consultation.

The SNP hopes the latest in Scotland's constitutional conventions would be independent of government. Nicola Sturgeon and her colleagues do not mean, I think, that there would be a bar on past or present politicians, far less on members of political parties. These, too, are "the people", after all. Common folk in the usual sense might wonder, nevertheless, about another private debating ­society stuffed, as ever, with the great and good.

Something else is missing from the proposals. Let's say the SNP's own offerings are variously amended, accepted, revised or rejected. A founding document for a new Scotland emerges. It expresses the highest aspirations. It might even count as an example to the world. As Sturgeon has written, it qualifies as "the highest and ­strongest of laws - a statement of the fundamental principles by which a country chooses to live". So do we get a referendum vote, being sovereign and all, on this fundamental text?

The heart might sink at the thought. What is being discussed is, in any case, no more than a ­transitional arrangement to be put in place until a convention sets to work. Nevertheless, the idea of giving all the people the final say seems to have been overlooked. The need to entrench a ­constitution and put it beyond the whims of a ruling Holyrood party has also been neglected. And as Tickell has argued, it is still not clear that we understand what "we" mean by "the people".

Still, set this beside the old shell game of Westminster and virtues emerge along with the problems. If a constitution is to give voice to a nation's sense of morality, to take the conspicuous example, it makes sense to put in law the belief that the country should not house ­weapons of mass murder. This ought to be no more contentious than saying that all are equal before the law. Some still affect amazement, nevertheless, at the SNP combining constitutional reform with party political manifesto commitments.

British governments have long resisted written constitutions for the simple reason that, unless you happen to be called Stalin, such documents get in the way. Sturgeon's guarantees for education, housing or the environment are laudable in general and tricky in particular. Such is not the people's problem, and nor should it be. But the absence from the bill of any proposal for a truly supreme constitutional court is something no serious convention should overlook.

For now, all is theoretical, the stuff of hopes and dreams. That is, of itself, part of the process, and another reason why Scotland's debates are attracting attention below the Border. In England people are asking again why a famous "evolving" but unwritten constitution is still tolerable in the age of rights and responsibilities.

Here we are reminded that we are indeed the people. If we don't ­understand what that means, we can begin to find out, and begin to make a reality of things we can ­imagine. Anyone who doesn't find that a little exciting should be granted the constitutional right to remain comatose.