I WANT to start with a belated best wishes to Nicola Sturgeon, who reached her half century last week.

Congratulations, First Minister. Enjoy it. You’ll be 60 in no time.

If you think that’s a little harsh, don’t. Politicians are always thinking ahead like that, as we saw in the recent flurry of MSPs announcing their exit at next year’s Holyrood election.

“I will be 67 this summer and 72 at the end of the next parliament,” sighed the SNP’s Mike Russell as he waved farewell to his Argyll & Bute seat.

Labour’s Iain Gray felt the same shudder of tempus fugit in East Lothian: “The decision to stand down is not an easy one… however I will be 64 next year, almost 69 by the end of the next parliament.”

The First Minister also showed her dread of a drive-by shooting from time’s winged chariot in interviews on the occasion on her birthday.

“I am a bit perplexed as how, suddenly, I’m 50,” she said in one.

“I think, with politicians, there must be something about living in four or five -year election cycles - suddenly four of them have gone past and that’s 20 years of your life.”

It wasn’t the only interesting thing she said. In another birthday piece, she spoke about life after power.

“While I’m not planning for it to be imminent, whenever I do stop being first minister – because every first minister has a shelf life – I will still be young enough, and hopefully healthy enough, to go in a different direction and do other things. I find that is something that is quite uplifting.”

It’s always intriguing when leaders broach their political mortality.

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Can you imagine Ms Sturgeon in her pomp after the 2015 general election raising the prospect of life after politics? It wasn’t so much as a dot on the horizon back then.

Now it’s not just on her mind. The thought of embarking on a new career is actually “quite uplifting”.

Clearly doing a five year stretch in Bute House transforms the soul.

So let’s consider what the next electoral cycle or two might bring.

Although most commentary right now is about the coronavirus and the constitution dominating the 2021 vote, and whether Indyref2 or economic recovery takes priority, I suspect another big strand will be the shelf life Ms Sturgeon mentioned.

She will have been First Minister for six and half years on election day, and will be asking for up to five more.

That would take her to just 40 days shy of Margaret Thatcher’s marathon rise and fall of 11 and a half years.

Ms Sturgeon is therefore bound to be asked ad nauseam in the campaign if she would serve out a full term.

As her party’s buoyant popularity is inextricably bound up with her own ratings, she would have little option but to say that she would, with gusto.

But would Ms Sturgeon follow through on her pledge?

Bear in mind it implies she would try to outdo Mrs Thatcher by standing again at the 2026 election as well, as she wouldn’t have given her party time to pick a new leader before then.

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Thoughts of her shrinking shelf-life and the Enoch Powell adage that all political careers end in failure would surely be crowding in by that point.

The next Holyrood term or two will be unforgiving. The economic pain left by Covid will be long and grim.

Deep recessions and popular governments are rarely seen in each other’s company.

It will be an extraordinary slog. Or rather, another extraordinary slog.

Nor is there much sign of relief on the independence front. Even another SNP majority is not going to melt Boris Johnson’s self-interested heart.

He does not want to risk a second referendum and have the end of the Union on his political headstone.

With Labour recovering under Sir Keir Starmer, Mr Johnson’s best electoral days already seem behind him. Given the Tory party’s ruthless form with malfunctioning leaders he’ll be lucky to last a couple of years.

No need to make the inevitable more wretched by losing Scotland into the bargain. His successor won’t want to start with Indyref2 either.

Which means that, on top of the economic problems, Ms Sturgeon can expect years of anger from the Yes movement about the lack of a plan to overcome Westminster’s entirely predictable referendum blocking.

In truth, the muttering and mumping is pretty loud already.

But if the 10th anniversary of 2014 arrives without a big change in outlook, it will become deafening.

However there is an escape clause in Powell’s famous quote.

It reads in full: “All political lives, unless they are cut off in midstream at a happy juncture, end in failure, because that is the nature of politics and of human affairs.”

So far, no First Minister of Scotland has found that happy juncture.

Death and defeat have been the way, then obscurity or notoriety.

Donald Dewar died after barely a year in office. Henry McLeish quit over an expenses fiasco. Jack McConnell lost the 2007 election. Alex Salmond lost the referendum.

Could Ms Sturgeon be the first to do it her way? Might she decide that, given her inevitable expiry date, a fresh start is best begun at a time of her choosing, rather than be forced out of office on a bum note?

In less than two electoral cycles she really will be 60, and that window to a different life will be closing fast.

I wonder... Anyway, from an envious 51-year-old, Happy Birthday.