When it comes to tailored clothing, most of our traditions derive from British society, where men of a particular social class used to have separate wardrobes for town and country. Town, in this case London, was where people conducted business while wearing dark worsted suits, white dress shirts, dark ties and black Oxford shoes. The country, such as the sporting estates in Scotland, was where people hunted game while wearing brown thornproof tweeds, cream tattersall shirts, pebble-grain shoes and wool challis ties with little motifs on them.

In this world, dress codes were governed by time, place and occasion. Country clothes were for the country, city clothes for the city, and never shall the two meet. That’s how we get the phrase, “no brown in town”.

Few people follow such strict rules anymore, but this logic still shapes how we see formality in clothing. Formal clothes, such as what would have been worn for business, are defined by slick, smooth materials such as Super 100s wool. Casual materials, eg, those worn for sport, are rougher, fluffier and feature a more visible weave.

When deciding whether a suit jacket can be worn on its own, first inspect the fabric’s texture, fibre, colour and sheen. Wool is generally considered more formal than linen or cotton, which means something like a ribbed corduroy or rumply linen suit jacket can always be worn on its own. But even within wool, there are distinctions. A smooth, silky wool jacket with a slight sheen, especially when made in a dark sober colour such as charcoal, will very obviously telegraph “business”. Conversely, a rougher tweed in an earthy colour such as olive or brown can more safely be worn on its own.

Certain patterns can also be tells. Historically, pinstripes and chalkstripes were worn by executives and bankers, making them among the most formal of patterns. The same pattern – a stripe – is made much less formal when it’s the boating variety. Those loud, broad stripes were worn by members of rowing clubs, making them inherently casual.

The same is true for other patterns. Fine patterns, such as bird’s eye, nailhead and pinhead, are naturally reserved for business. Herringbone and Glen checks, on the other hand, can be either large or small, with the larger versions being considered more casual. As a general rule of thumb, the larger and louder the pattern, the more likely you can wear it as a sport coat, whereas small, fine patterns in quiet, faint tones should be reserved for suits.

During the early 20th century, a Neapolitan man named Mr Vincenzo Attolini, who was then working as the head cutter at the bespoke tailoring firm London House (later renamed Rubinacci), borrowed a page from Mr Domenico Caraceni’s tailoring book on how to make suits and sport coats softer.

At the time, British tailoring was the North Star and the small number of tailors located up and down Savile Row mostly set the standard for men’s tailoring. Attolini bucked the norms by ripping out all of the stuffing that made British tailoring so distinctive – the stiff layers of canvas, padding and domette, which constitute the structure that defined London dress. In their place, he used a softer canvas and a little bit of horsehair to create shape. This is how Neapolitan tailoring was born – a version of British tailoring that was better suited for warmer Neapolitan climes and which looked more casual.

The distinction between softer and stiffer tailoring continues to shape how we see formality. A strong, padded shoulder will look relatively more formal and even militaristic, almost crying out for the sharp lines on a pair of tailored trousers. Conversely, a minimally padded jacket with softer lines and naturally shaped shoulders will be easier to dress down.

Consider the jacket's silhouette when deciding whether a tailored jacket can be paired with jeans. A heavily structured jacket, even if made from semi-casual materials such as tweed, will be more challenging to dress down than a jacket with a slouchier silhouette.

The same is true for jeans. Overly slim, low-rise cuts will be harder to wear with tailored jacket, whereas something like OrSlow’s mid-rise 105 (a slim-straight leg) and 107 (a slim-tapered) will be easier to wear with a tailored jacket because the cut evokes a kind of classic mid-century aesthetic.

Small details can also make a suit jacket look more convincingly like a sport coat. Iridescent mother-of-pearl buttons, such as what you might see on a tropical wool or linen jacket, will make the garment look a little more casual. A suit jacket with sleeves featuring one-, two-, or three-button cuffs will look less formal than if the sleeve had four buttons. Finally, patch pockets will always look a little less formal than flapped pockets, which, in turn, look less formal than their jetted counterparts.

Ultimately, dress is a kind of visual language. Like any language, it takes a bit of knowledge and practice before you become fluent, at which point, you’ll know when things “sound right”. Once you become aware of how formality is expressed through the details in tailored clothing, things will become second nature. Had DeSantis taken the stage that January night while wearing a textured, matte navy jacket with iridescent mother-of-pearl buttons and patch pockets, he wouldn’t have looked like he was dressed for a remote work Zoom meeting.