THE First Minister has sent my congratulations.

To be fair, he's sent your felicitations too. In fact, Alex Salmond has decided that we are, each of us, "absolutely thrilled" by news of a birth in London. If only referendums could be won with such intuitions.

Before the ear-bending starts, let me state that I wish no ill to any child. All new parents have my best wishes. But thrilled? Not exactly. No insights into the tenacity of constitutional monarchy are needed to find the scenes in England's capital a bit depressing. The appetite for a republic has diminished: so much was self-evident. Who knew that a fertility cult was preferred?

The airwaves are full of happy chatter. Much of the noise has been generated by the House of Windsor's surfeit of heirs to the throne. Soon enough there will be three chaps waiting in the wings. If you believe some commentators, the supply of monarchs is guaranteed for at least another century.

Thanks to bitter experience, the royals know that things are rarely so simple. The value of one's mystique can go down as well as up. Stuff happens; times change; gratifying opinion polls breed complacency. For now, nevertheless, the republican threat, such as it ever was, has been seen off. Happy thoughts have trumped rational thoughts.

A lot flows from the fact. One is that real reform of Westminster government has been postponed indefinitely. The apparatus of the Crown-in-Parliament, the politicians' invisibility cloak, will endure. Prerogative will keep accountability at bay for a few more generations. Committees of the Privy Council will go on taking care of those bits of business with which voters need not trouble themselves. Who, celebrating the birth, actually cares about how their country is run?

In theory, Mr Salmond cares a great deal. When he spares us the historical nonsense of a "queen of Scots" he has plenty to say about issues such as the privileges of the Crown Estate. He doesn't always join the dots, however, between his sentimental regard for the monarchy and royal realities. As republicanism retreats, the SNP's convenor prefers affection, loyalty and deference.

He seems sincere enough. Since the Windsors are more popular then ever, according to the London chorus, the First Minister would probably be unwise to adopt any other position. But the bald facts of royalty's resurgence conceal an interesting sub-text where Scotland is concerned. It is pointless to pretend that we live in a republican redoubt, but the idea that Scots are as loyal and true as the Home Counties is far wide of the mark.

On a couple of occasions this year the YouGov polling organisation has included questions about the royals in its surveys. These tend to generate simple headlines when the balance of opinion across Britain is calculated. Pry into the regional breakdowns for the numbers, however, and a more interesting picture emerges. It doesn't amount to a fundamental disagreement, but with the monarchy "more popular than ever", there is a marked divergence.

In March, for example, YouGov wanted to know who, if anyone, should succeed the Queen. The all-British figure matched the headlines: 44% said Charles; 37% said William; and only 12% said the monarchy should end. In the south of England, only 9% wanted neither prince to succeed. In Scotland, the figure was 24%.

In June, similarly, respondents were asked if they had positive or negative views of the Queen. With "very positive" and "fairly positive" combined, the monarch scored 82%; in London, the figure reached 86%. Totted up, her "negatives" were just 12% in Britain and a mere 9% in London. In Scotland, 23% were fairly or very negative towards the venerable figurehead.

That still left 70% of Scots with a favourable attitude towards the Queen, of course, and 7% who didn't know what they thought, or didn't care one way or the other. Still, as enthusiasm for another heir wells up in London and spreads, according to David Cameron, across "the nation", the statistical differences are not insignificant. Given recent history, these polls are probably as good as it gets for the royals and HM's loyal Scottish subjects.

In London, according to YouGov, 62% think positively of Charles and 28% are negative. The equivalent Scottish figures are 50% and 43%. Is this because the Duke of Rothesay is a problematic figure? If so, the numbers for the couple of the hour – gathered before the birth, admittedly – take some explaining. Even after those happy days spent at St Andrews, 22% of Scots have negative feelings towards William and 26% hold similar views on Catherine. The British averages are 11% and 12% respectively. But so what? As a monarchist would no doubt point out, these royal personages are vastly more popular in Scotland than any politician. Dissent is an affectation of the churlish minority. Any republican who makes anything of these numbers is clutching at straws.

Perhaps so. They are substantial straws, for all that. The YouGov surveys were taken before the birth but after a royal wedding and a year-long Jubilee waged like an elaborate campaign to win affection. Both the First Minister and the palace can probably live with that. A 70% to 24% split allows better odds for royalty in Mr Salmond's idea of an independent Scotland than it does, according to most other polls, for independence itself. Nevertheless, if 24% are "negative" now, what would follow the next spot of Windsor bother? Given the family's history, the one certainty is that the immunity conferred by a new baby will be temporary.

Something else needs to be noticed as viewers, listeners and readers are conscripted to monarchism's cause. Few of the Scots who can't be doing with royalty have thought hard or long about the alternative. To declare yourself a republican is one thing. To think through what it actually means is another matter. Scotland isn't there yet. But a royal scandal – one of the few things guaranteed in this life – never hurts.

For now, the Windsors are winning. There is no point in denying it. You can't compete with an infant any more than you can reason with a mob. Sixteen years ago I was one of those listening to Elton John and the Anglican liturgy in Westminster Abbey. Had you told me the royal house would recover triumphantly from the funeral for Diana, Princess of Wales, I would have asked if you hallucinated often. It might even have gone into print. Once the Queen was gone – I was certain about this – they were finished. Scandinavian discretion and reduced circumstances were their best hope. The idea of Charles badgering ministers with intemperate letters behind the scenes, far less being allowed to keep such letters secret, was unthinkable. But like a lot of people, I didn't think hard enough.

Happy monarchists should pause, nevertheless. If the monarchy's revival seemed absurd in September 1997, its plight, thanks to Charles and Diana, would have sounded unimaginable just a generation before. Arguments are not settled by the arrival of children.