PHILADELPHIA — Like desperate shoppers fighting over a hot toy on Dec. 24, rival shopping networks QVC and HSN are waging war over the slogan "Christmas in July."

Both networks promote shows with that title in July, offering viewers a chance to stock up early on a $53 porcelain holiday cat or $36 lighted wreath.

Now they are competing over the name in U.S. District Court in Philadelphia.

QVC argues that it started its "Christmas in July" program first, in 1987. But the smaller HSN — aka the Home Shopping Network — was the first to the door of the U.S. patent office in 2000.

QVC lawyer Manny Pokotilow argues that the West Chester-based company had what is known as a "common-law" trademark for using and promoting the name, even if it never registered it.

"We assume that there may have been actual confusion, ... that someone assumed they were dealing with QVC," Pokotilow said. "The question is whether or not there has been damages. We don't know."

HSN ignited the fight when it sent QVC a cease-and-desist letter last year — but now argues that neither side can lay claim to the common phrase.

"A search on Google will turn up many, many references to 'Christmas in July,' " said lawyer Edward Colbert, who represents St. Petersburg, Fla.-based HSN. "We don't know the basis on which QVC is claiming complete and exclusive rights."

Legal skirmishes over seemingly generic phrases are nothing new. In 2002, the Todd M. Beamer Foundation fought for the right to use the Sept. 11-inspired phrase "Let's Roll!" even though other people, hoping to cash in on the slogan, applied first. The foundation has since allowed Wal-Mart and the Florida State football team use the morale-boosting motto.

And in an oft-cited trademark case, Ringling Bros. and Barnum & Bailey sued Utah's tourism department for using the slogan, "The greatest snow on earth." A federal appeals court found the slogan did play on the circus' trademarked slogan, "The greatest show on earth," but said Ringling Bros. did not prove actual damages.

A Google search of the phrase "Christmas in July" turns up 481,000 hits, from a 1940 movie about a lovelorn office clerk to a charity motorcycle ride in Illinois.

"It seems to me extremely unlikely that anyone would hear the phrase 'Christmas in July' and think of either of these TV channels," said University of Pennsylvania law professor Polk Wagner. "It seems like a fairly common phrase that's used in retail establishments all the time. ... That's the basic problem the parties have."