Two multi-billion branding behemoths have made power moves this week.

Firstly, there is Nike unveiling its sponsorship with Colin Kaepernick, the take-a-knee quarterback at the centre of the culture wars.

Secondly, there is John Lewis & Partners invoking two pop culture fail-safes – Dougal Wilson and Bohemian Rhapsody – to announce its new partnership message and co-branding with Waitrose.

In the case of Nike, the debate is already raging about whether it’s an inspired piece of purpose-led branding bravery, or a cynical monetisation of resistance.

And in the case of John Lewis, most of the focus will be on the direction of the ad (Dougal Wilson doing what he does brilliantly) and the visual side of the Pentagram rebranding (the monotone John Lewis subliminally channelling Project Fear).

But at the eye of these two branding storms, there should be one small area of calm agreement. The writing is brilliant.

Whatever you think of Nike’s motives, and whether or not you believe it’s the right strategic move, the headline is an example of an entire $28billion brand teetering on whether the copywriter gets the next word in the sentence right. You could have exactly the same strategic thought and art direction, but if one nuance in the copy is wrong, it would be a fatal flaw.

What’s so good about the line? Firstly, the opening echoes the standard Nike voice of using a direct imperative, even following the same three-word pattern. Just do it. Believe in something. Then the second part nails that powerful balance of ‘something/everything’, in a way that does what a good rhetorical device always does – it makes it sound like it makes sense, even before you work out whether it actually makes sense.

What could have gone wrong with the line? Lots of small things – for example, a comma in the middle instead of a full stop would have made it sound less Nike. But also some bigger things. If the second line said ‘Even if it costs you everything’, it would mean the same thing, but would also invite the snapback: ‘Yeah right, wonder how much he got paid for that ad.’ You can make the same smart reply with ‘sacrificing’, but it’s not an open goal in the same way. ‘Sacrificing’ has a religious quality that goes well with ‘Believe’ and shifts it away from associations with money.

Aside from the wording, there’s also the relationship of line and image. The primary way in which you read the line is as a statement about Colin Kaepernick – he is the hero of the ad, with Nike as the celebrator of the hero. That’s a better place for a brand to be, rather than casting itself as the hero or ‘leader of the conversation’ (Hello Dove, Hello Pepsi, Hi Heineken). Of course, the secondary message is that Nike is the hero too, by risking its own brand in order to take a side, but it matters that it’s the secondary message.

As a side note, I’ve seen people saying ‘Yes! This is how you do brand purpose’. But it isn’t – it’s just how you do a good ad. Nike has always had pictures of athletes with an inspiring headline. This is exactly in that tradition – on brand and product-focused. Put Chelsea Manning in the ad instead of Colin Kaepernick and you would have a good example of a ‘brand purpose’ ad – co-opting an unrelated cause in a way that bears no relation to the brand. The message would be the same, but the cultural meaning would be radically different.

The purpose of Nike remains to sell cool trainers. The responsibility of Nike (and the brand positioning of Nike) remains to be a clued-up corporate citizen that shares values with its target audience. That’s a different thing, and easier to achieve when you recognise it’s not your purpose – the creative tension with the profit motive is the whole point. There are some great examples of organisations who have a purpose beyond profit – they are called not-for-profits.

Anyway, John Lewis. In many ways, the ad is everything I find tiresome about John Lewis ads. Twee rendering of 70s/80s song, Boden-catalogue children, Middle England wish fulfilment fantasy. But it’s also genius – a brand returning to a winning formula at a critical time.

And it is a critical time strategically – the decision to emphasise the partnership message and the overt co-branding with Waitrose is a major corporate move with much at stake. Most of the attention will be on the visual side of the rebranding by Harry Pearce at Pentagram. I suspect it will work well long-term, although Middle England will initially lament the monotone John Lewis.

But there’s a single line at the heart of the rebranding, which also forms the endline on the Dougal Wilson ad. ‘When you’re part of it, you put your heart into it’. For me, that’s the anchor that holds the whole operation in place. Or to mix metaphors, the North Star that will guide John Lewis through the storm.

Anyone working in branding and advertising will know there are about 5,000 PowerPoint slides behind that line. Big circles saying ‘Functional benefits’ and ‘Emotional benefits’. 50-page presentations on the internal and external meaning of  ‘partnership’ and how it maps onto the desire paths of key stakeholders.

Somewhere in the middle of all that, a copywriter will have sat quietly and thought about how you make the argument in everyday language that means something and sounds good. ‘When you’re part of it, you put your heart into it’ doesn’t sound like a genius headline in the same way as Nike. But it’s doing an equally big job, equally well.

It gently employs something known as the Keats Heuristic – the idea that we’re more likely to believe something if it rhymes. And the two rhyming words are the key words in the whole argument – part and heart. ‘Part’ is the functional message about how John Lewis/Waitrose is structured differently to most of its competitors. ‘Heart’ is the emotional benefit that comes out of it – the idea that people invest more in their work when they feel a sense of ownership. Somehow, all those PowerPoint slides have collapsed into a short line using everyday words that have a gentle musicality to them and a ring of proverbial wisdom.

The other writing that appears in the John Lewis rebrand is less remarkable – ‘For us, it’s personal’ is fine, but has been used by a thousand brands before. But that part/heart line is a massively valuable piece of branding wordsmithery which probably won’t get the attention it deserves.

And that’s my main take-away from both Nike and John Lewis – whatever else they are, they are definitely stories about copywriting at its best. For me, the ability of copywriters to take big, complex, high-stakes arguments and render them in everyday, memorable language is one of the most enduring and magical things about advertising and branding. On both sides of the Atlantic, it’s brilliant to see we’ve still got it.

Nick Asbury is a writer at Asbury & Asbury, author of Perpetual Disappointments Diary, and scribbler of realtime poetry on Instagram