Williams-Sonoma went into San Francisco federal court Tuesday with its claim that Amazon.com has created “a fake Williams-Sonoma website” on its platform, while Amazon argued for the right to resell others' merchandise without having to face ginned-up claims about consumer confusion.

Orrick Herrington & Sutcliffe partner Annette Hurst for Williams Sonoma and Durie Tangri partner Mark Lemley for Amazon ran into a judge who admitted to being a power user of Amazon. U.S. Magistrate Judge Elizabeth Laporte of the Northern District of California said it's clear to her personally that when Amazon adds the words “by Williams-Sonoma” to Williams-Sonoma merchandise, that simply means Amazon is acting a reseller, which is legal.

But she said several times during an hour-long hearing that adding words like “Amazon official site” and “by Williams Sonoma” may be just confusing enough for ordinary consumers to defeat Amazon's early-stage motion to dismiss the case.

“Why add that?” Laporte asked Lemley. She said it seems “gratuitous, but I don't think Amazon [does anything] gratuitously, at least not for long.”

Lemley said the “by Williams-Sonoma” tag appears in small text, as a link to a page with other Williams-Sonoma merchandise. If it weren't there, he said, Williams-Sonoma would probably be suing Amazon for offering its products without being forthright about the source.

“Well, depending how this lawsuit turns out, you may or may not be immunized by another lawsuit,” Laporte said with a chuckle.

Williams-Sonoma kicked off the dispute in December by accusing Amazon of trading on Williams-Sonoma's goodwill and infringing its service mark. Williams-Sonoma says it carefully guards its online reputation, and calls Amazon's use “a counterfeit mark.” Amazon moved to dismiss the case in February, saying it had a right under the first-sale doctrine to accurately identify the merchandise it's reselling.

Tuesday's hearing featured two of Silicon Valley's premier IP lawyers. Lemley brought his professorial approach to the argument, except for when he accused Hurst of rigging her complaint so that any appeal would go to the Federal Circuit. Hurst, meanwhile, brought up U.S. Sen. Elizabeth Warren's call to break up Amazon over alleged anti-competitive behavior at one point, which Laporte quickly shut down.

For her own part, Laporte, in what she called the “true confessions” portion of the hearing, described her own impressions as an Amazon user. “They're basically taking over the world. They sell everything. Pretty soon, nobody else will be left,” she said with a laugh. “When my husband first got Prime I thought it was a terrible indulgence. But before long I became addicted.”

She said that “personally, my own instinct” is that Amazon is right about what the language on the site means. “But I do then have to … put that aside, because I'm not the target consumer here reading this,” she added.

Lemley said the allegations would have weight only if Amazon suggested “full, official endorsement” by the Williams-Sonoma. But Amazon isn't doing that, he said, and the Ninth Circuit has discouraged suits based on vague claims of confusion. “If we just said, 'Well, people might be confused,' everything would get to trial, and I think the courts are trying to short-circuit that,” Lemley said.

“Well, I don't know about 'get to trial,' but might get past motion-to-dismiss stage,” Laporte replied.

Hurst said the Ninth Circuit's first-sale caselaw allows only the stocking and reselling of a third party's goods. Use of phrases like “Amazon official site” are “wholly unnecessary to convey the information to the consumer,” she said. “They're advertising the mark, not the good, and they're doing it in a way that suggests endorsement, sponsorship or affiliation.”

If Amazon's conduct is so egregious, Laporte asked Hurst, why haven't other merchandisers complained?

“Some may simply not want to fight,” Hurst said. “You have presidential candidates trying to break them up because they're misusing their status as a platform to acquire data that they then use to compete with retailers.”

“Whatever the other unhappiness may be, I'm just focusing on this one,” Laporte told her. “I'm not getting into those other things.”

Lemley, meanwhile, argued that not only Ninth Circuit but also caselaw at the Supreme Court and Federal Circuit supports his position.

“You had to drag the Federal Circuit in,” Laporte said.

“Unfortunately, counsel has dragged the Federal Circuit into it,” Lemley said. “There's a reason there is one design patent on a single chair” included in the complaint, “and that is to send this case to the Federal Circuit.”

“I've got to object to that,” Hurst interjected. “In fact, there are more design patents coming. But attribution of motivation is improper.”

“I'm ignoring that,” Laporte assured her.

In the end, Laporte complimented Hurst, Lemley and Durie Tangri's Allyson Bennett on their “extremely well presented” argument. “Which of course,” she added, “doesn't make it an easier question for the court.”