Last week, when I reported that Judge Pauline Newman of the U.S. Court of Appeals for the Federal Circuit wants her colleagues to clarify the standard for issuing pre-trial injunctions in patent cases, I listed the four prongs of the preliminary injunction test federal judges are supposed to apply: likelihood that the plaintiff will prevail on the merits; irreparable harm to the patent holder absent an injunction; the balance of equities; and the public interest. Judge Newman wants the appeals court to revisit a ruling that making it easier for patent defendants to counter the first element of the test. But in the biggest injunction case out there right now, the fourth prong is shaping up as a critical consideration.

On Friday, San Jose federal judge Lucy Koh ruled that Verizon and T-Mobile can submit amicus briefs opposing Apple's bid to enjoin the sale of Samsung's Galaxy cellphones and tablet computers. (As usual, Florian Mueller at FOSS Patents was first with the news.) With Apple's injunction motion scheduled for an October 13 hearing, both wireless carriers argued that they're already marketing Samsung products for the upcoming holiday season, so a bar on sales would not be in the interest of the shoppers who want to buy Galaxy devices. "The timing of such an injunction on two popular consumer products that will help anchor 2011 holiday sales would unnecessarily harm T-Mobile and thousands of U.S. consumers," wrote T-Mobile's K&L Gates lawyers in their amicus brief, which contends that Apple doesn't need a preliminary injunction because it can always recoup money damages if Samsung's products are later determined to infringe Apple patents.

Verizon's brief, filed by Kellogg, Huber, Hansen, Todd, Evans & Figel, adds the argument that Samsung products operate on the 4G network, which has cost Verizon big bucks to develop. Barring Samsung phones would severely restrict consumers' 4G options, Verizon claims, and could cripple the network. "The harm from an injunction would go well beyond Verizon Wireless and consumers," the Verizon brief said. "It would hurt U.S. businesses, U.S. job growth, and access to emergency personnel." (Did you get that Apple? If a heart attack victim has to dial for help with a 3G phone because he couldn't buy a Samsung device, it's on your head!)

Verizon spokesman Jeffrey Nelson told me that Verizon-which only recently hooked up with Apple to support iPhones--is just trying to support competition in the marketplace for mobile devices. "We have a pretty important position that needs to be heard," he said. "In a way, we're not taking sides. We believe consumers have to have access to the latest devices."

Apple's lawyers at Wilmer Cutler Pickering Hale and Dorr and Morrison & Foerster had asked Judge Koh not to admit the amicus briefs because T-Mobile and Verizon waited too long to file them, leaving Apple insufficient time to respond. (I called both Harold McIlhenny of MoFo and Bill Lee of Wilmer but didn't hear back.)

Judge Koh did agree with Apple that there's no need for T-Mobile's lawyers to argue at the Oct. 13 hearing. "T-Mobile is not a party to this litigation, and the attorneys from Samsung and Apple are fully capable of arguing the issues without the assistance of third-party counsel," she wrote.

Final briefs are due in the next couple of days. Samsung's lawyers at Quinn Emanuel Urquhart & Sullivan didn't respond to my phone messages.

(Reporting by Alison Frankel)

Follow Alison on Twitter: @AlisonFrankel 

Follow us on Twitter: @ReutersLegal