WASHINGTON >> A conservative Indiana lawyer engineered the string of legal victories that have enabled corporations and wealthy individuals to channel tens of millions of dollars into this year’s midterm elections secretly, a study by campaign watchdogs has found.

James Bopp Jr., a Republican-backed lawyer from Terre Haute, Ind., who has fought campaign finance laws for 30 years, filed the lawsuit that led to last January’s Supreme Court decision allowing unlimited corporate and union dollars to bankroll independent election ads.

Bopp said he is now challenging laws in Hawaii and other states including— California, Florida,  Iowa, Maine, Minnesota, Ohio, New York, Rhode Island, Vermont, Washington and Wisconsin — that require disclosure of the names of campaign contributors.

Some of those cases, Bopp said, challenge requirements to disclose all donations of $25 or more, a threshold he considers too low.

“James Bopp is the point man for conservative wealthy interests whose goal is to dismantle the laws and regulations we have in place to stop the buying of Congress and other elected officials,” said former Rep. Bob Edgar (D-Penn.), the president of the liberal-leaning lobby Common Cause.

Labor unions also have capitalized on the relaxed rules to spend tens of millions of dollars from their treasuries this year, but there is no mystery about the source of their funds: members’ dues.

By Sunday, nonprofit groups backing Republican candidates or opposing their foes had spent $105 million, compared with $61.7 million by those supporting Democrats, according the Washington-based Sunlight Foundation. However, national Democratic Party committees had narrowed the gap by doling out $67.9 million, outpacing their Republican counterparts by more than $7 million.

Prominent outside groups that support Democrats are in the game, too. Abortion-rights group Emily’s List and the liberal activist group Moveon.org, for example, have spent less than $1 million combined so far, and they have disclosed their large donors.

Common Cause and another liberal-leaning group, Public Campaign, commissioned Klein Research Services to conduct the study of Bopp’s record, headlined “The Man Behind Our Secret Elections.” McClatchy obtained an advance copy.

Reached by telephone, Bopp chuckled at the findings and said: “Oh gosh, this is probably the most credit I’ve ever gotten. And I already think I get an unwarranted amount of credit, because judges write the opinions.”

While the study cited a statement in which he purportedly said he had a 10-year plan to dismantle campaign finance laws, Bopp said that came from a joke he made earlier this year.

“I said I had a 10-year plan in my head,” he said. “There’s no 10-year plan. There’s just things I think about.”

The study said that Bopp has served as both a legal defender of and a recipient of political cash from undisclosed donors, in addition to payments of more than $1 million since 2003 from the Republican National Committee.

Bopp said that he has crusaded against both federal campaign donation limits and disclosure requirements because he thinks corporations have First Amendment rights in election campaigns and shouldn’t be “punished” with negative publicity for exercising them.

A series of court cases spearheaded by Bopp, his nonprofit James Madison Center for Free Speech and other conservative legal centers have unraveled key underpinnings of the 2002 McCain-Feingold campaign finance law, which Congress enacted in an effort to plug the unlimited flow of cash into federal elections.

The court rulings, capped by the Supreme Court’s Citizens United decision early this year, reversed the prohibition on the airing of campaign-season issue ads that identify candidates, but don’t directly support or oppose them. The high court also lifted a long-standing ban on independent corporate spending to influence elections.

The rulings, however, left intact a bar on direct corporate donations to political campaigns, and the Supreme Court appeared to encourage rules to require disclosure of the donors’ names. Eight of the nine justices concurred in a section of the opinion that envisioned “effective disclosure” of donors’ names via the Internet, available to voters.

However, the Federal Election Commission implemented the ruling more narrowly, requiring only identification of contributors who designate money for specific advertisements, not those who donate for general campaign themes.

In the past, conservative legal strategists argued that full, timely disclosure of the sources of campaign money is all that’s needed to regulate campaign spending. Now, said Paul Ryan, a lawyer for the Campaign Legal Center, they seem to have changed their minds.

A McClatchy review of recent FEC reports has found that the court’s action and the FEC’s implementation of it have enabled special interests to pour big bucks into this fall’s races, often without disclosing the sources of the money. 

Take the political committee American Crossroads, created by Karl Rove, the chief architect of George W. Bush’s two presidential victories, and former Republican National Committee Chairman Ed Gillespie. The group has identified large donors, some writing seven-figure checks, to finance the nearly $16 million it has spent to support Republican congressional candidates since Sept. 15, mainly in 10 key Senate races.

However, Crossroads Grassroots Policy Strategies, a sister group that operates from the same offices, hasn’t disclosed the identities of any of the donors who’ve bankrolled $11 million in expenditures for GOP candidates, especially in seven Senate contests.

Yet another group sharing the office suite, the tax-exempt American Action Network, headed by former Republican Sen. Norm Coleman of Minnesota, has spent $3.3 million directly supporting GOP candidates or opposing their Democratic rivals and $14.8 million more since Sept. 1 on issue ads naming candidates, also without disclosing its donors.

Both Crossroads GPS and the American Action Network have claimed 501(c)(4) tax-exempt status, which is permitted only if influencing elections isn’t the groups’ “primary purpose.”

They’ve kept their donors’ names secret under a rule that exempts those who didn’t designate their money for specific ads. Democratic Sen. Max Baucus of Montana, the chairman of the Senate Finance Committee, has asked the Internal Revenue Service to investigate the legitimacy of such groups’ tax status.

Other examples:

—The U.S. Chamber of Commerce created a tax-exempt entity to air issue ads as part of its campaign for a Congress that is friendlier to business. The new rules require these groups to identify donors who give $1,000 or more to back such campaign communications unless the money doesn’t go for particular ads.

Citing the breadth of its campaign, the Chamber has declined to identify any of the contributors who have financed more than $32 million in expenditures through Friday.

—The Club for Growth, a political action committee that has backed GOP candidates for years and some anti-tax tea party candidates this year, found a way to assist its former president, Pat Toomey, in his campaign to succeed Sen. Arlen Specter of Pennsylvania, who lost the Democratic primary to Rep. Joe Sestak.

While Toomey’s campaign, like all others, is constrained by a $2,400 limit on donations from any one individual, the newly formed Club for Growth Action Fund solicited unlimited donations and has spent at least $3.9 million aiding GOP Senate candidates, including $2.1 million to help Toomey against Sestak.

—According to the Sunlight Foundation, the Citizens for a Working America PAC has spent $250,000 to oppose the re-election of Rep. John Spratt (D-S.C.), the chairman of the House Budget Committee. The group reported one donor: New Models, a Virginia-based tax-exempt group that doesn’t reveal its contributors.

Bopp said that some conservative tax-exempt groups have begun collecting donations of less than $1,000, putting them into separate accounts for use in financing ads so the donors don’t have to be identified and “drug through the mud” even if they bankroll specific ads.

While large campaign donations can corrupt a candidate, Bopp said, “There is literally no evidence that independent spending corrupts candidates.”

Ryan counted that that under the current rules, “it’s extremely easy to launder your money through a harmless-sounding group like Americans for America, while hiding the identity of arguably less-popular true funders.”