Interests supporting a controversial bill aimed at improving cyber security, set for a House vote Thursday, spent 140 times as much lobbying Congress as those on the other side of the debate and have dozens of former Capitol Hill insiders working on their behalf, an analysis by the Sunlight Foundation's Reporting Group shows.

Sunlight's review of lobbying disclosures from the last session of Congress in Influence Explorer shows that backers of the Cyber Intelligence Sharing and Protection Act had $605 million in lobbying expenditures from 2011 through the third quarter of last year compared to $4.3 million spent by opponents of the bill. While it's impossible to say how many of those dollars were devoted to trying to influence votes on the CISPA bill (many of those entities have multiple interests before Congress), it provides some measure of the lopsidedness of the resources available to each side.

SEE THE DATA: Here are the lobbying totals for the CISPA supporters and opponents.

Despite that, the fight is far from over. While the bipartisan bill is expected to pass the House, critics believe they have the advantage when the debate moves to the Senate. Moreover, the Obama administration announced Wednesday that the president will veto the bill in its current form because of privacy concerns.

Reps. Dutch Ruppersberger (left) and Mike Rogers, CISPA's sponsors

The CISPA backers' advantage in the House comes, at least in part, from support of lobbying behemoths like the Chamber of Commerce, IBM, which sent nearly 200 executives to Capitol Hill Monday to advocate for passage. Also backing CISPA: major tech, telecom and financial companies, a Who's Who of the biggest spenders on Washington lobbying.

The imbalance is also evident in the number of former staffers and members of Congress pushing for CIPSA. Among them: former Reps. Steve Largent, R-Okla, who represents the wireless industry, Dave McCurdy, D-Okla., of the American Gas Association, and Cal Dooley, D-Calif., of the American Chemistry Council. McCurdy chaired the House Intelligence Committee in the early 1990s. The panel's current chairman, Mike Rogers, R-Mich., drafted the CISPA bill.

More than 60 companies and associations have signed on to letters of support to the intelligence committee in support of the legislation, aimed at facilitating the sharing of cyber threat information between the private sector and government.

Opponents are a group of more than 50 civil liberties organizations, digital rights groups and Internet companies like Craigslist (whose founder, Craig Newmark, is a member of the Sunlight Foundation's board) and Reddit. Most don't have lobbying budgets at all. Some do, like the American Civil Liberties Union, which ran a full-page ad in Politico this week. The ACLU spent more than $2.7 million lobbying in the last session of Congress. Other opponents of the bill that have lobbying budgets of $100,000 or more are: the U.S. Public Interest Research Group, the American Library Association and the National Association of Criminal Defense Lawyers.

Campaign giving edge

Maplight has already shown the campaign finance advantage of the pro-CISPA groups -- they have donated 16 times more than CISPA opponents to current members of Congress in a two-year span from 2010 to 2012. The bill is seen as industry-friendly, as it offers companies liability protection if they share a threat with the government. It also does not require them to delete personally identifiable data.

The bill overwhelmingly passed the House Intelligence Committee 18-2. Authored by Rogers, it's also backed by the panel's top-ranking Democrat, Dutch Ruppersberger of Maryland.

Opponents are counting on a strong netroots pushback. The Electronic Frontier Foundation says the fervor is stronger than it was during the backlash that torpedoed the once-bipartisan bill that rankled Internet activists -- the Stop Online Piracy Act (SOPA).

Opponents of the CISPA bill are hoping their work will pay off in a similar fashion.

"It’s not the same as SOPA and PIPA but it’s the sort of thing where we kept people informed for a long time until people finally started paying attention," said Emily Sheketoff, the executive director of the Washington office of the American Library Association.

“I think we’re going to continue to see high levels of Internet engagement on this issue," said Rainey Reitman, activism director of the EFF, which has sent forwarded more than 70,000 letters from people opposed to CISPA to their members of Congress. "The Internet has become a very politicized force for bills that affect Internet rights."

Anti-CISPA petitions

Other groups, including Free Press, Fight for the Future, Demand Progress and the American Library Association have also launched efforts to innundate Congress with letters, phone calls and emails opposing the bill.

An anti-CISPA petition on Avaaz.org reached over 800,000 signatures; a petition against the bill on the White House garnered more than 100,000 signatures, the number required to prompt a response from the administration.

Spokespeople for companies and associations supporting CISPA either declined to comment for this story or did not respond.

The Senate is writing its own version of cyber security legislation, based on a bill that failed to move last year.

"The Senate is where you go kill bills," Reitman said. Even if a Senate bill proceeds, she called it "an entirely different beast" because it included more privacy protections, though it was still troublesome, she said.

Another heartening sign for Reitman is that some companies that supported CISPA in 2012 are now longer doing so -- namely, Facebook and Microsoft. However, the trade association Tech Net, which represents tech giants Microsoft and Google, sent a letter backing the bill.

The cracks in the anti-SOPA coalition are a complicating factor, opponents of the CISPA bill acknowledge. “There’s this sense that – Why can’t you just flip a switch and do another one of those?" Reitman said, referring to the activism that helped kill SOPA.

“But," she added, "it didn’t happen overnight."