“This emergency Budget deals decisively with our country’s record debts.” That was the very first line of the very first Budget speech that George Osborne ever gave. For me, it rather sums up his attitude back then. He wasn’t just the Submarine Chancellor, only surfacing from the depths of the Treasury to deliver a Budget or an Autumn Statement. But, whenever he did surface, it would be on a sure bearing. Decisive. Confident. Cocksure, even. It was almost as though just saying the words would make it so.

That’s changed in recent months. For starters, Osborne no longer spends so much time underwater. In January alone, he went from waxing enthusiastic about the Coalition’s economic plan to advocating a rise in the minimum wage to emphasising that tax cuts will first be directed at the least well-off. That this coincided with a period of silence from Ed Balls was convenient, for it suggested a new way of things: the Chancellor is fully present, while his shadow is just a shadow.

But, more importantly, Osborne has also become more restrained. He no longer creates the impression of Godlike abilities, but dwells on his – and the wider world’s – very human limitations. This was becoming clear in that New Year speech, the most telling passage of which read:

“…there’s no point pretending that there’s some magic wand a Chancellor can wave to make the whole country feel richer than it actually is – or that I can control the global oil price from an office in Whitehall.”

Yet it’s become clearer still during the past week. Not only have we had him quelling the notion that Help to Buy will fix the housing market:

“Across the board, we are pulling a lot of levers. But this is a historic problem … I don’t pretend this problem is going to be solved in a few months or a couple of years.

This is a big challenge for our country. We have got to build more homes.

I imagine if we were to assemble again in 10 years’ time we would still be talking about the challenge of making sure our housing supply keeps up with demand.”

We’ve also seen him try to dampen speculation about shale gas:

“I am very pro this development and I think it does have the potential to bring gas prices down in the UK.

I just don’t want to over-promise. I don’t want to go out there and say this is the solution to all of this country’s economic problems.”

I’m not claiming that Osborne never said anything like this before – in fact, he made the point that “British Governments are not in charge of the world’s oil price” in his second Budget speech. Nor am I claiming that he is no longer given to fanciful rhetoric. But the balance is certainly different. He now points exaggeratedly at the bounds of Government policy. The caveat has greater status.

Which brings us crashing into the question: why? And the most obvious answer is Government. We all know that old saw about campaigning in poetry and governing in prose. Another way of saying it would be that you campaign with dreams and govern with facts – and the facts have not been kind to the Chancellor’s original dreams. Just look again at the declaration from the start of his first Budget: “This emergency Budget deals decisively with our country’s record debts.” Back then, he expected to get the debt on a downwards trajectory before the end of this Parliament. Now, it’s unlikely to happen before 2017-18.

Yes, in Government, Osborne has been constrained by everything from the absence of growth to the demands of Coalition. He’ll now be aware, more than ever, that there’s no point promising the Earth when you might only get a handful of mud. As he put it in his New Year statement, “It’s simply not being straight with people.”

But I wonder whether there are other factors at play. One of the strangest things about Osborne’s new demeanour is that he’s adopted it at a time when the economy, as well as his own stock, is rising – but perhaps that’s the point. The strategist in him may figure that it’s easier to be “straight with the people” (and with the markets) when they don’t think you’re doing a bad job overall. He can now count on a whole bucketload of sugar to help the medicine go down.

And then there are this Chancellor’s ambitions. At a time when authenticity is prized, but lacking, among politicians, it may be no bad thing for him, personally, to highlight his limitations. Why try to stride around like a colossus when voters would prefer a person? This fits in with other Osbornian trends that I’ve mentioned before. Where he once came across a calculator wrapped in a suit, he now tweets photos of dogs and cats.

On which note, you might not believe me when I say that this is worth keeping an eye on. But it is. Whether the Chancellor retains his new persona, or whether he starts talking as though every possibility is limitless again, it could have a bearing on the Tories’ election campaign. Will he want to set his hardboiled prose against Miliband’s student poetry?