After paying $612.5 million to settle a patent lawsuit with NTP this year, BlackBerry maker Research In Motion probably hoped to stay out of court for a while. No luck. It's back in, facing a rival that already has one key court victory behind it.

Visto, which sells mobile E-mail technology to wireless carriers, last week won a case in which a federal court ordered Seven Networks to pay it $3.6 million in damages for patent infringement. Emboldened by the win, Visto attorneys that same day filed a lawsuit against RIM, claiming it infringed on four of its patents, three of which are identical to those in Visto's lawsuit against Seven. RIM has about 5 million customers.

RIM co-CEO Jim Balsillie was quick to call Visto's actions a "brazen strategy" to sue everyone in the mobile E-mail business, including Microsoft and Good Technology. RIM says it's been monitoring Visto's litigation against the other companies and believes Visto's patents are invalid. It reassured customers they wouldn't be impacted by this latest lawsuit.

But RIM has reason to worry. "It will be more difficult for RIM to disprove the patents because they've already been validated in court during the Seven trial," says attorney Steven Lieberman of Rothwell, Figg, Ernst & Manbeck.

RIM has better things to spend its money on than court settlements. It's trying to expand into consumer markets. Last week, it made a pitch for small businesses with a free download of its server software, eliminating a big cost barrier in that market.

Still, a lot of signs point to a settlement. RIM settled its case with NTP despite that vendor's having a number of its patents ruled invalid by the U.S. Patent and Trademark Office, rather than risk having its service shut down by a court injunction. That pressure will hang over this case, too--even if these settlements start burning a bit of a hole in RIM's wallet.