The report went mostly unnoticed outside Anchorage. But its conclusions suddenly loom large in the current debate over nonprofit advocacy groups like Americans for Job Security, which campaign watchdogs say allow moneyed interests to influence elections without revealing themselves. Congress is now wrangling over a bill that would require some disclosure.

With every election cycle comes a shadow army of benignly titled nonprofit groups like Americans for Job Security, devoted to politically charged “issue advocacy,” much of it negative. But they are now being heard as never before  in this year of midterm discontent, Tea Party ferment and the first test of the Supreme Court decision allowing unlimited, and often anonymous, corporate political spending. Already they have spent more than $100 million  mostly for Republicans and more than twice as much as at this point four years ago.

None have been more active than Americans for Job Security, which spent $6 million on ads during the primary season. This week, emboldened by the court ruling, the group paid close to $4 million more for ads directly attacking nine Democratic candidates for Congress. That made it among the first to abandon the old approach of running ads that stopped just short of explicitly urging voters to elect or reject individual candidates.

Americans for Job Security says it is careful to hew to tax and campaign-finance laws: It may not spend the majority of its resources on political activity or coordinate with party committees, and may keep its donors secret only as long as their contributions are not intended for specific ad campaigns close to an election. Instead of earmarked donations, the group says, it collects membership dues and then decides, on its own, how to spend the money.

“We believe issue advocacy is much more effective than banging down doors of members of Congress,” said the group’s president, Stephen DeMaura. “And you now have the Supreme Court of the United States reaffirming our rights.”