A couple of months ago, Twitter made a pledge that is heartening to anyone sick of patent lawsuits. The company will not use any patents derived from employee inventions to launch offensive lawsuits without the inventor’s permission.

The pledge might help Twitter attract ethical engineers, but ultimately it’s just one company taking a stand among a sea of litigators that are happy to prevent the sale of competitors’ products or extract licensing fees. A potentially more ambitious project called the “Defensive Patent License” aims to take the same basic idea practiced by Twitter and spread it across a big part of the technology industry.

Developed by Berkeley Law professors Jason Schultz and Jennifer Urban, the Defensive Patent License (DPL) project has been in development well before Twitter’s pledge. The project just launched its website and the legal document members will be asked to commit to.

Any company that commits to the terms of the Defensive Patent License would have to pledge all of the patents it owns to this league of do-gooders. Any other member of the league would gain a free license to any other member’s patents, and no one in the league would be allowed to launch offensive patent lawsuits against other members of the league. Doing so would be grounds for the member to have its license revoked.

You can sue anyone except your friends

“The idea is if you want to be part of this network of defensive patent people, you are committing that all of your patents, every single thing you’ve done, will be available royalty-free to anyone who wants to take a license, if they commit to only practice defensive patent licensing,” Schultz said today in Boston at the Usenix conference on cyberlaw issues. “As long as they don’t offensively sue anyone else in that network, everything’s cool.”

The commitment is both daunting in that it requires submitting all of a member company’s patents to the pool, and forgiving in that members can still sue the pants off non-members. Schultz said his team thought long and hard about the exact implementation of the Defensive Patent License.

The “all-in” provision was put in place to prevent companies from joining the network while only providing their lamest patents. The ability of DPL members to sue non-members, meanwhile, preserves the right to monetize inventions. It also keeps members on a level playing field with non-members.

Schultz and others who spoke at the cyberlaw conference said they’re not opposed to intellectual property rights, per se. Patents and copyrights provide incentive to innovate, after all. But, like many observers of the technology industry, Schultz believes patent litigation has gone too far.

Some entities opposed to patents have decided to opt out of the patent system entirely. Schultz believes this is also the wrong approach, because it eliminates the possibility of using patents defensively to protect yourself from attack. Additionally, if legitimate inventors don’t patent their innovations, others can come along and claim ownership of ideas and technologies they didn’t create.

Patent hoarders may have little incentive to join

As the defensive network and its stash of patents grows, so does the value of membership. But, as one Usenix attendee asked, would a big company with loads of patents (like IBM or Microsoft) have any incentive to join? Schultz didn’t have a great answer to that question, noting “this is one of the reasons we’re still tweaking the license a bit.”

One method of attracting big companies would be allowing them to pledge only a portion of their patents. But as noted earlier, this approach was rejected because “[i]t’s too hard to police the gaming where people would just put in their junk patents and keep the good ones out,” Schultz said. Big players such as Red Hat, Sony, and IBM have joined a similar patent consortium called the Open Invention Network, but they aren't required to commit all of their patents to that group.

Schultz and Urban laid out their arguments in a paper on the Social Science Research Network. This garnered a response from prominent IP lawyer David Hayes and Eric Schulman, Google’s director of patents.

Hayes and Schulman note that the DPL could bring substantial benefits if it grows large enough, and suggest changes that might help attract big companies to the DPL. As constructed today, the DPL disproportionately benefits members with small or non-existent patent portfolios, Hayes and Schulman argue. One change they suggest is a carveout for “cloning” and “foundry” products or services, limiting the concern that members might practice “wholesale product copying” of other members products. They also suggest tweaks to the circumstances under which DPL licenses may be revoked.

Schultz acknowledged the concerns, but he seems confident that DPL gets the major parts right. That includes providing a sensible definition of “defensive patent claim” that lets members use their patents to protect themselves (such as with a countersuit against a party that launched an offensive suit) without being so broad as to render DPL commitments meaningless. The DPL also ensures that patents committed to the pool don’t lose their restrictions in cases of the patent owner going bankrupt or selling the patent to another company.

“This set of promises creates a network of patent holders who are publicly and legally committed to defensive uses of their portfolios vis-a-vis each other,” Urban wrote in a blog post on the Defensive Patent license site. "DPL users are free to demand licensing fees or bring infringement suits against anyone outside of the DPL network, but they must remain defensive within it. Like the IPA [Twitter’s Innovator’s Patent Agreement], the DPL’s obligations ‘travel with the patent’: in the event that a patent is sold, its new owner also must abide by the DPL’s terms.”

Disincentives for patent trolls

It’s hard to see the DPL having any major impact on the types of lawsuits we see today. Certainly, Apple, Microsoft, Oracle, Samsung, Yahoo, Motorola (now owned by Google), and all the other litigious members of the tech industry aren’t about to lay down their arms.

Urban notes in her blog post that both Twitter’s pledge and the DPL are “a private response to a broken patent system,” but “unless and until Congress or the courts can improve things, such private solutions may be our best options to stem the rising tide of patent attacks.”

Regardless of the likelihood of success, it’s an intriguing idea. Even if it has no impact on the IBMs and Microsofts of the world, it might make trouble for patent trolls. If a patent has been de-weaponized, there’s no reason for a troll to buy it, Schultz said.

“The trolls won’t go after the DPL people because they already have an irrevocable license, forever, for free,” he said. “We think this will decrease the weapon supply of trolls.”