Debate on a bill seeking to curb the worst practices of so-called "patent trolls" has been postponed four times in the past two weeks as Senate Judiciary Committee chairman Sen. Patrick Leahy (D-VT) seeks to nail down votes in support of the bill.

The repeated delays mean that Congress will head home for two weeks without having passed the bill out of committee, a step that reformers were ardently hopeful would come to pass. It's a potentially alarming delay since there are just 39 days left before the Senate's August break. Congress will return to work in September, but with an election campaign in full swing at that point, it's unlikely that any significant legislation will pass.

However, late yesterday Leahy's office said that a "manager's amendment"—that is, the chairman's preferred draft of the bill—will be circulated to the committee members the day they return from their two-week break. The committee will consider a bill the first week that Senators are back, which is the week of April 28.

"We have made enormous progress, and we now have a broad bipartisan agreement in principle," said Leahy. "This is a complex issue and we need additional time to draft the important provisions that have been the subject of discussion."

Sources lobbying both for and against the bill said that the past two weeks have been largely opaque for negotiations, with Senate staffers keeping the discussions behind closed doors. But yesterday's announcement about the "broad agreement in principle" has given hope to reformers, who got most, but not all, of what they were looking for in a version of the bill that passed the House of Representatives in a 325-91 vote in December.

"It's a little disappointing that there's a delay, but frankly everything we're hearing is good news," said Julie Samuels, who has lobbied in favor of a reform bill in her former capacity as an EFF attorney and now as head of Engine Advocacy, a group representing startups. "The senators are close to a deal, if not at a deal, that would have most of what's in the Innovation Act," the name for the anti-patent-troll bill that passed the House. "We just hope those measures are as strong as they were in the House bill."

Opponents, meanwhile, are scrambling, since they don't know quite what they're arguing against.

"We call on Senate leaders to share the details of the latest potential deal and include the leaders of America’s innovation economy in a collaborative process," read a statement from the Innovation Alliance, a group composed of the chief opponents to the bill.

The Innovation Alliance has been sending letters to Leahy and ranking committee member Sen. Charles Grassley (R-IA), with a growing list of more than 100 companies signed on, indicating that they don't support the bill as currently composed. "This tremendous surge in signees over just a few days really underscores the broad range of companies and organizations that have serious objections to the current direction of the patent proposals being considered," wrote an Innovation Alliance spokesperson in an e-mail yesterday.

Charles Duan, who has written in support of patent reform for the advocacy group Public Knowledge, said that he believes the delay is less about substantive disagreement and more about just hammering out the right language.

"There are also issues involving the discovery, in terms of how much they should legislate versus how much they should leave up to the judicial conference to make rules about these matters," said Duan.

Opponents of the bill include a variety of companies and groups that find themselves more often on the plaintiff side in patent litigation and deal less frequently with trolls. Those include pharmaceutical, biotech, and medical device companies, as well as heavy patent-licensors like Dolby and Qualcomm. University groups have also opposed the current version of the bill, although American Association of Universities VP John Vaughn told Ars that he believes there's room for a compromise version.

"If you work through it methodically enough, you can do a good job of targeting bad behavior and not sweeping in good behavior," said Vaughn. "The proponents have been pressing for very aggressive provisions. When you do that in a broad way, it really compromises the ability of patent holders to legitimately enforce patents."