As readers of 1066 and All That will recall, Oliver Cromwell and his supporters were “Right but Repulsive”. But both adjectives may be questioned by readers of Paul Lay’s Providence Lost, a spirited and vivid survey of the brief period in which Cromwell held the dangerously ill-defined role of “lord protector”.

The trial and execution of Charles I in 1649 had been a reckless, unpleasant and largely counterproductive piece of political theatre, but by 1652 parliament had passed the Act of General Pardon and Oblivion, which was in effect an amnesty for royalists prepared to accept the new status quo. Subsequent royalist plots, which were infrequent and incompetent, were handled firmly but with no gratuitous bloodshed or scorched-earth vengeance – the watchwords were “healing and settling”. Cromwell’s own passionate commitment to religious tolerance (stopping short of Roman Catholics, of course, who were assumed to be unreliable citizens by definition, devoted to a foreign prince, the pope) meant that the body count in denominational persecution was very low indeed.

This is perhaps why Lay devotes the best part of two chapters to discussing the unusual case of James Nayler, a wildly eccentric Quaker convicted of blasphemy in 1656. Parliament hesitated before imposing a penalty, since it was simply not sure what would be appropriate, and the suggestion from one pious idiot that the biblical punishment of stoning to death would be appropriate was roundly rejected. In the end Nayler was whipped, branded and his tongue bored through; bad enough, but the country had seen much worse. Cromwell took pains to distance himself from this judicial sadism; it is typical of his style of rule that he consistently held back from “exemplary” punishments and gratuitous cruelty.

Not entirely “Repulsive” then, even during the rather chaotic period of the Rule of the Major-Generals, which began in 1655 when the protector, having suspended parliament, redrew the map of England as a jigsaw of military governorships. The stubborn resistance of the traditional legal and social authorities in the regions – the squires and magistrates and the spiders’ webs of local family and interest – frustrated the plan to impose a uniform style of “godly” morality and to root out superstition, inherited cultures of deference and an excess of alehouses.

As Lay insists, however, this was never a military dictatorship in anything like the modern sense: absent were universal surveillance, an atmosphere of political denunciations, large-scale and bloody purges and reprisals. There were certainly vindictive fines heaped on obstinate royalist gentry, but these were not universal. The project was short-lived and effectively ended with the reassembly of parliament in 1656.

Yet the experiment of military governent shows how little view Cromwell and his circle had of what was politically “Right”. Far from having a single programme for political reconstruction, Cromwell havered, improvised and drew back from supervising details, as if to preserve “deniability”. It increasingly seemed as though the only two fixed points were his determination to avoid any legal privilege for a single Christian body in the state and his resolute resistance to being crowned as a monarch.

Very admirable, but it showed the growing distance between him and the great majority of parliamentarians, few of whom were dedicated republicans. While many wanted to overhaul the Church of England to make it Presbyterian like the Church in Scotland, most held to the idea of an established Church as a pillar of the “ancient constitution”. And that ancient constitution was what they felt the Civil War had been about; a monarchy accountable to a parliament that oversaw public spending and conserved the long-term financial interest and stability of English society.

Although he is only a shadowy presence in Lay’s book, the great parliamentarian commander Thomas Fairfax could be taken as a representative of all that Cromwell and the major-generals were up against. Fairfax was someone who had not favoured the king’s execution, who was rooted in a very traditional squirearchical order, who was mildly reformist in religion, who had a spectacular record as a soldier and who enjoyed near-universal trust and respect. When, after Cromwell’s death, the rule of his son Richard gently collapsed in less than a year, it was Fairfax’s final decision to re-emerge into public life and join General George Monck’s struggle against the radical republican troops that helped tilt the balance and pave the way for the return of the Stuarts.

Lay’s narrative identifies two fundamental problems that Cromwell’s regime was unable to resolve: one religious and one more narrowly political. Lay begins his book with a vignette of a small-scale colonial venture in the Caribbean – the settlement in the aptly named “Providence Island” (off the coast of what is now Nicaragua). The settlement was captured by the Spaniards in 1641, after persistent efforts to secure it as a bridgehead for English interest in the region and a colony of godly Protestants.

The high hopes and disastrous history of Providence Island provide a kind of metaphor for the way in which the appeal to divine Providence both energised and paralysed the Commonwealth regime. Later in the book we see how attempts to dislodge Spanish (and thus Catholic) hegemony in the Caribbean were seen as part of a God-given vocation for England to play its part in overthrowing the global power of the papacy. But the repeated failure of so many of these ventures was a matter of real spiritual torment to Cromwell, who felt it was obvious that God was punishing the English for their slowness in reforming religion and morality. The Rule of the Major-Generals was in significant measure an attempt to make up for what were seen as national sins.

As Lay says, the awareness of Providence looking over one’s shoulder must have been like an unbroken exposure to social media, without the option of switching off: a recipe for ceaseless anxiety and self-doubt. What we see of Cromwell in this book is mostly not what his allies and friends in earlier life had encountered: a jocular, informal, confident and companionable man, with virtually no formal military training but an exceptional capacity for intelligent off-the-cuff strategising. In a sense, it was all too easy to put down his unexpected triumphs to Providential intervention in favour of the godly. The downside was that failures, too, were Providential (rather than being ascribed, as the Caribbean disasters should have been, to poor planning, confused lines of accountability and some spectacularly inept leadership). The story of the protectorate is indeed a story of “Providence lost”, a growing confusion about where in history the hand of God could be seen.

It is a pattern familiar in revolutionary narratives: the point at which it ought at last to be obvious to all that the revolution was right and justified, when one could be confident of being on the side of history, keeps slipping over the horizon. Someone must be blamed and the revolution inexorably descends into factional warfare. In recent decades, analysis by political thinkers such as Raymond Williams and Gillian Rose has stressed the inevitability of “long revolutions”, and the dangers of messianic end-of-history aspirations and the bloodshed that accompanies them. This should remind us of the foolishness of speaking as though history had “sides”, yet still the left and the right resort to such defaults. Lay’s book sheds light on this process, despite the fact that Cromwell’s must have been, historically, one of the least terror-ridden of revolutions.

Cromwell had inherited an already deeply divided coalition of interests. There was a solid ballast of constitutional monarchists, who looked back to a largely fictional but emotionally potent ideal of a monarch governing in harmony with a devolved and “nested” set of authorities, shaped by the ethos of common law, precedent and recognised liberties. For such people, parliament was the necessary vehicle for supervising national affairs, keeping the sovereign from absolutist habits and ruinous expenditure.

This “civilian” party, as Lay calls it, was confronted by a much more radical group, focused on a hugely expensive standing army. Confident and aggressive, it was dominated by principled republicans and contained a wide range of religious radicals who were impatient with constitutional tradition and willing to explore far more egalitarian ideas.

For neither the first nor last time, the elusiveness of the British constitution led to substantial confusion – though also to some creative thinking. Lay points to The Commonwealth of Oceana, a work by James Harrington published in 1656 at the height of the conflicts around the Rule of the Major-Generals, which argued for radical land reform and a bicameral system of an elected (republican) government with a strict rotation of members over three-year periods. It would have pleased neither parliament nor the army, but it remains a remarkable essay in constitutional thinking – better suited to a smaller polity, as its references to the contemporary Venetian system might imply.

But Cromwell’s problem was that while he could not govern without the army (and thus without guaranteeing finance for the army – a huge and growing challenge), he also could not do away with the parliament for which his supporters had fought in the Civil War. He had repeatedly tried to manage without the House of Commons and it had not been a success; the major-generals had not been able to secure the large-scale national funding that only parliament could produce and approve, and the circle resisted squaring. At a more theoretical level, there remained an issue about legitimacy – in the absence of the monarchy, where exactly did legal sovereignty ultimately lie? This was where the unhelpful ambiguity of the role of protector became an issue and is why so many pressed Cromwell to simply accept the title of king, if only because the legal institutions of the country understood its meaning.

The end of the story is familiar: the collapse of the republic and the return of the Stuarts, who were a good deal more vengeful towards their predecessors than the Commonwealth had been. Plus the eventual triumph (no thanks to the Stuarts) of something vaguely like the agenda of the “civilian” parliamentarians in the shape of the Whig ascendancy, though still shot through with the ecclesiastical and hierarchical notions that had been embedded in the ancient constitution.

Lay is quite properly sparing with contemporary lessons to be learned, but reading this at the beginning of 2020 does give one a few things to think about. Representative parliamentary government may be a thorough nuisance to a hyperactive executive, but it is one way of securing the voice of minorities somewhere in the national decision-making process and is a necessary source of legitimacy for allocating national resources. At its simplest – as the Commonwealth experience rather shows – it is a check to the politics of mere force, whether military or populist.

And there is another thought that might be worth pondering in the light of Cromwell’s career. In the end, he proved inflexible about a small number of things and evasive or undecided about a much larger range of policies. He may have been right about the matters on which he refused to compromise but on other issues he failed to craft a clear shared “platform” with a reliable group of colleagues, which could have been a clearly and commonly owned programme capable of intelligent scrutiny and defence. This was partly due to his profound anxieties about Providence – a personal form of political destiny, cut off from the more resourceful general schemes of political theology that both Catholics and Calvinists had to offer. But it is also an index of what can happen to a skilled local tactician suddenly obliged to shape a sustainable political culture and a prolonged and complex conversation about shared goods.

No facile crossovers to the 21st century, agreed, but the events of the past few months have given us a lot to think about in terms of our expectations of political leadership. Doing so with Cromwell in mind might prove illuminating.

Rowan Williams is a lead book reviewer for the New Statesman

Providence Lost: The Rise and Fall of Cromwell’s Protectorate

Paul Lay

Head of Zeus, 352pp, £19.99