ONE of the oldest questions in political theory is whether we should put our trust in “Good Laws” or “Good People”.

Does the well-being of the state depend principally upon its laws, rules, institutions, and impersonal processes? Or does it depend upon the moral character, public spirit, and civic virtue of those in power?

James Harrington, an English republican constitutional theorist writing in 1653, thought that good government was a piece of cake.

­Imagine two children who are given cake to share between them. How can they achieve a just distribution?

One way would be for each of the children to be pure-hearted paragons of self-denying virtue, dedicated to the well-being of the other – good character and unselfishness would ensure that neither would want or take more than their fair share.

If, however, one of the children should be subject to the normal human frailties and give room in their heart to greed or pride, then the other would be cheated. If they do not wish to be cheated, they must reciprocate, using ­craftiness and guile, or force and domination, to defend their rightful interest.

READ MORE: David Pratt: The bloody power struggle in Sudan has wide implications

Once those forces of humanity’s darker ­nature are unleashed, it would be hard for them to stop; they will inevitably go beyond the boundaries of their rightful interest and seek to possess more than their share of the cake.

That way lies a potential for prolonged conflict. The cake will be stale before either of them get to eat it.

Both lose from the lack of cooperation.

One approach is to create strong social mores, norms, and conventions of behaviour, which will keep wayward wants within their proper bounds.

Perhaps notions of shame, ­continually reinforced by everyone in the children’s ­social circle, will be enough to act as a ­disincentive – no one wants to be called a greedy guts. ­

Perhaps there will be sanctions of various kinds, ­informally enforced by social pressure: the child who develops a reputation for taking more than their fair share of cake will be shunned by their classmates whenever the birthday party or sleepover invitations are handed out.

But there is another way, and that way is to get together before the cake is touched and agree upon a simple rule – that one shall cut, and the other chooses.

The one who chooses always has the ability to choose the larger slice. The one who cuts therefore has the incentive to cut as accurately down the middle of the cake as ­possible.

The beauty of that latter system is that it does not depend upon the moral virtue, the ­self-restraint, or the generosity, of either child. The virtue lies in the system – in the structure of the rules. It is sufficient only that they agree to those rules and stick by them.

If they do that, and nothing more, then the fairness of the ­process and outcome will be assured, even if both children are as greedy, sneaky, and prone to temptation, as most of us are.

To ask whether we should depend on good character or good rules and institutions to ­secure the common good and the public ­interest against corruption and misrule is a bit like ­asking whether a bird flies on its left wing or its right one – both are needed, and they must beat together.

They are mutually reinforcing. Good ­people will tend to improve and strengthen the ­institutions and rules around them. Good rules and institutions will tend to shape people’s ­behaviour and encourage them to be good.

The so-called “British constitution”, however, lacks rules and institutions that can constrain the government.

The doctrine of parliamentary sovereignty means that there is really no such thing as a constitution at all, in the sense of a supreme and fundamental law that the government of the day cannot unilaterally change.

READ MORE: Ruth Wishart: The Tories’ favourite flip-flopping peer is at it once again

As Sir Ivor Jennings put it in 1950: “The ­British constitution provides no check against a ­Conservative government which really ­intended to go authoritarian – because a ­government which has majorities in both Houses can do what it pleases through its control of the ­absolute authority of Parliament.”

In the absence of constitutional constraints that would institutionalise virtue, the British system is wholly reliant upon the self-restraint of those in public life. It flies on one wing. If that virtue falters – as it most obviously has – then we are all left in jeopardy.

“But amongst you, it shall not be so.”

Scotland must not replicate the faults of the British state. That means having a proper constitution.

It also means reforming party governance structures. Recent difficulties in the SNP ­remind us that it is folly to place our trust in the sinlessness of powerful people. Human nature is too fragile for that.

To repair the damage, and avoid future ­calamities, the SNP needs institutional reform – including a clear separation between the ­party and the government, and stronger internal party mechanisms that can hold the leadership to account.

Last week’s TNT show on TikTok was a hit, so look out for another surprise this week. Join us on IndyLive at 7pm on Wednesday