A long-sought patent reform bill was foundering in the House on Wednesday as leadership faced a multipronged uprising from within the GOP ranks over issues ranging from union influence on the Patent and Trademark Office to how the program is paid for.

Majority Leader Eric Cantor (Va.) had hoped to pass the bill Tuesday. But with divisions in his caucus continuing to stall the measure, K Street sources said leadership is struggling to round up enough GOP votes to pass the measure.

Leadership aides, however, downplayed the effect of GOP objections to the bill, arguing that Republican opposition remains minimal and that Cantor expects to have work on the measure wrapped up by the end of the week.

Still, lawmakers were not so sure and argued the fight is a continuation of two decades of dispute over the bill.

“This is not the first time. The same people are involved. It’s the same issue,” said Rep. Dana Rohrabacher (R-Calif.), an opponent of the bill. “They’ve been doing it for 20 years, and we’ve been thwarting them for 20 years.”

The legislation includes sweeping changes to the Patent and Trademark Office. Although it has brought a number of business interests together ­­— most notably retailers and bankers — the bill has sharply divided Republicans along a number of fronts.

During a morning conference meeting Tuesday, those divisions were on full display as a number of lawmakers launched into long diatribes against the bill, Republicans said.

For instance, Rep. Virginia Foxx (R-N.C.) reportedly used the meeting to raise objections to a lack of controls on the union representing workers at the PTO, and aides said she and other social conservatives want the House to use the bill to rein in the union.

Other Republicans, such as Rohrabacher, have been angered by the bill’s handling of small investors. Rohrabacher said Tuesday that he used the caucus to express frustration with the bill’s “first filer” provisions, which he argued would benefit large corporations over individual inventors — and would then force the public to foot the costs.

“We’re not only siding with the big guys against the little guys, we’re taking taxpayer money and giving it to the big guys,” he said.

“They’re going to bleed the little guy … so the little guy will never get through the system without cutting a deal with the big guy and getting paid a pittance” for his invention, Rohrabacher added.

Still other conservatives, particularly among the freshman class, have raised objections to the bill’s constitutional underpinnings, while other lawmakers have objected to the fact that the Appropriations Committee will maintain control over the fees collected by the PTO from inventors.

How far the divisions go is unclear, but aides acknowledged there is growing concern that the bill may not have enough votes. One aide pointed out that former Judiciary Chairman Jim Sensenbrenner (R-Wis.) and Rep. Don Manzullo (R-Ill.) were actively whipping colleagues against the bill during a midday vote Tuesday.

One veteran GOP aide said part of the problem is that the bill is broad enough that it allows opponents to target different constituencies within the GOP for lobbying, pressing their case on social issues with conservatives such as Foxx while targeting fiscal conservatives on the bill’s costs. “The longer it hangs out there, the more they can pick off,” the aide said.

Even if House Republicans manage to pass the bill by Friday, it faces an uncertain future in the Senate. Sen. Tom Coburn has consistently opposed the fee provisions in the bill, insisting that the PTO be given full control of them.

Given his use of the chamber’s rules to tie legislation in knots, Senate GOP aides predicted the Oklahoma Republican could block the measure if it arrives with the House language intact.