It is an unfair and brutal truth: "The more women talk, the more men turn off," says Nina McLemore. "One of the challenges for women is to learn to say fewer words in a lower voice."

To be clear, McLemore does not condone this prejudice. As a former executive at Liz Claiborne, she has always encouraged women to speak up. But she is a pragmatist. "We have unconscious biases we don't know we have and not a lot of control over. We have to accept it and work around it."

McLemore is not a speech coach or life coach. She is a fashion designer who advises female clients on how to dress for work - to land the promotion, reel in a client, state her case and win the election.

In particular, she has made a name for herself with her softly tailored jackets, which, over the years, have shielded and celebrated women such as Federal Reserve Chair Janet Yellen, Supreme Court Justice Elena Kagan and, the self- described "pantsuit aficionado" herself, presumptive Democratic presidential nominee Hillary Clinton.

These are blazers you probably have not even noticed. You are not supposed to.

As the retail industry suffers a multitude of upheavals, the McLemore jackets have filled a niche, overlooked by the likes of Giorgio Armani and St John Knits, as the uniform for a woman of a certain level of authority.

They are not only designed to balance out a woman's proportions or distract from a problem area, but also to communicate power. Power accessorised with a pair of sensible pumps.

Her signature jackets are cut with a narrow shoulder and a full back. "Women are self-conscious about the shoulders being too big," she says.

But a woman has to be able to raise a gavel or gesture emphatically, so McLemore eschews the tight, high armholes favoured by high-end designers.

Her sleeves run about an inch longer than average and she crafts 21/2-inch-lined cuffs so a woman can turn them up in a get-to-work posture.

This aesthetic quirk also allows women to buy them off the rack without seeing a tailor to adjust the sleeve length. Women, McLemore says, do not like dealing with a tailor.

The collars stand up to frame the face and to elongate the body. And McLemore is not going to mince words: Long and lean is good.

McLemore came to be the guru of the power set after a dozen years at Liz Claiborne, where she launched accessories and sat on the executive committee.

A few women with sizable incomes and plenty of clout - bankers mostly - complained to her that they could not find anything to wear to work and asked whether she, as a favour, would help them shop.

After marching these women in and out of boutiques along New York's Madison Avenue, McLemore recognised their problem.

High-end fashion lines had turned their focus towards trendy customers from China and other developing markets rather than cater to the more quotidian needs of those in retail-saturated United States.

When other designers talk about their inspirations, they often drift into poetic reveries about an art exhibition that moved them, a film that haunted their dreams or a landscape that left them in awe.

McLemore, on the other hand, is more likely to explain her creative process with sentences that begin with "There's a very interesting study".

People's brains, she says, make snap assessments about people that can determine everything from who gets hired to who one talks to at a cocktail party. One remembers how someone looked more often than one remembers what he said. So, look capable, look confident and look good.

Of all her designs, three jacket styles stand out: the Suzanne, the Retro and the Car Coat.

The Suzanne, which is Senator Elizabeth Warren's preferred silhouette, flatters slender women with lines that gently follow the body. A jacket with a size-eight bustline, for example, eases out to a size 10 at the hips.

The Retro is a bit longer, covering the tush - Mrs Clinton wears it a lot. The Car Coat is longer still - it is the style McLemore suggests for taller women or those who are thick in the middle, but with skinny legs - a shorter jacket would make them look like "a box on toothpicks".

Every inch of a McLemore jacket is in service to her customers' authoritative image - there are no flights of fancy.

Being on the public stage makes a woman subject to scrutiny. But it is also an opportunity, McLemore says.

The question to ask is not "What do I want to wear?" but "What impact do I want to make?".

WASHINGTON POST