Ask a fashionista what a red soled shoe means and they’ve got two words for you: Christian Louboutin. (On the other hand, ask a guy what a shoe with a red sole means and they’ll probably answer: dirty shoes). Christian Louboutin believes the red sole defines his brands identity, so in 2008 he trademarked his red sole with the US Trademark office. Today, Christian Louboutin has a “zero tolerance policy” when it comes to enforcing his trademark (and if you’re looking for a working definition of “zero tolerance,” it might look something like this video of a monster truck rolling over thousands of counterfeit Louboutins). He has even sued brands such as Carmen SteffensOh. . . Deer, and more recently Yves Saint Laurent for violating this trademark.

Is Louboutin overreaching by claiming proprietary rights in red shoe soles? The answer might have Yves Saint Laurent’s lawyers seeing red.

As we’ve long tried to teach you here at Law Law LandTM, trademark law protects the name or mark associated with the product to which it is attached. You can trademark everything from the name of a product to the catch phrase or symbol representing that product. For example, McDonald’s hasn’t just trademarked the word “McDonald’s”; it has claimed trademark rights in the Golden Arches, as well as its numerous catch phrases (such as “I’m lovin’ it,” “Have you had your break today?” and “We swear we won’t make you as fat as that Super Size Me guy”…I might have made up that last one). Charlie Sheen is even trying to trademark his crazy rants (such as “Duh, winning,” “Tiger blood,” “Adonis DNA,” and “I’m Not Bi-Polar, I’m Bi-Winning”…impressively, I didn’t have to make up any of those). But let’s not open the can of crazy that is Charlie Sheen.

You can also trademark a sound (like MGM’s lion roar or NBC’s chime), and — as Louboutin knows — you can, indeed, trademark a color. Starting a delivery business? You’ll be doing your employees and yourself a favor by avoiding that special shade of brown ugliness that has, in fact, been trademarked by UPS. Similarly, Veuve Clicquot has trademarked its orange label, Owens Corning has exclusive rights to pink fiberglass, and Tiffany blue really is Tiffany’s blue. These trademarked colors are called “trade dress” and can be protected if consumers associate that feature with a particular brand or manufacturer rather than the product in general. However, the features will not be protected if they confer a function or competitive advantage (so if soles of shoes could only be made in red, then Louboutin wouldn’t be able to trademark a red sole).

While Louboutin has the “biggest respect for the house of Yves Saint Laurent,” he believes that he must vigorously enforce his trademark, lest he open the door for other brands to copy him and jeopardize his own brand. (Little does Louboutin realize that he hasn’t just stated a sound business principle, he’s also recited the law — trademark owners who fail to enforce their marks actually risk losing them as a matter of law.) And, since this is the law we’re talking about, naturally there is some sort of standard that Louboutin has to overcome before he can prevail on a suit for trademark infringement. The test is “likelihood of confusion,” as in the consumer is going to be confused as to the source of goods. While the factors vary slightly from jurisdiction to jurisdiction, generally, the courts will look at the strength of the mark, the proximity of the goods, the similarity of the marks, evidence of actual confusion, the similarity of marketing channels used, the degree of caution exercised by the typical purchaser, and the defendant’s intent.

Given that list of factors, trademark infringement cases are highly fact-intensive, and the court’s decision will be based on how it balances those factors, which side hires the better experts to make their case, and whether the judge is a shoe fanatic. And it’s a pretty close case. Louboutin’s lawyers will argue that (1) the marks are identical (red sole), (2) consumers are very likely to get confused (unless you grab someone’s foot to look at the brand stamp inside or at the bottom of the shoe which would likely subject you to an assault and battery charge), and (3) the shoes are sold in similar stores and marketed to a similar demographic (people who can spend $500+ on a pair of shoes). On the other hand, YSL will argue that (1) the existence of color-matching shoe line shows a lack of infringing intent, and (2) people who can spend $500+ on a pair of shoes are sophisticated enough to know exactly what they’re buying. In the meantime, though, things are already getting ugly, as YSL has defended itself by calling the lawsuit “absurd,” claiming that Louboutin fraudulently claimed exclusive use of red soles in his trademark application, and accusing Louboutin of illegally trying to monopolize a style that has been used in footwear from 17th century Europe to The Wizard of Oz.

Given the high stakes and substantial resources of both parties, the lawsuit is likely to go on for years. So for now, put that bottle of red nail polish away and don’t go painting the sole of your shoes red — or else you might be walking right into the middle of a trademark lawsuit.