Gov. Jerry Brown campaigns on behalf of Proposition 30, his tax measure. The nonprofit Americans for Job Security donated $11 million to oppose the measure in what California authorities called "campaign money laundering." (Gary Friedman, Los Angeles Times / ) 
 
 WASHINGTON — Tax-exempt advocacy groups that played an aggressive role in this year's election are coming under increasing scrutiny from state regulators, who are cracking down on organizations seeking to engage in campaigns without revealing their financial backers. 
 
 The pressure in states with stringent campaign finance rules contrasts sharply with the federal level, where nonprofits that spent hundreds of millions of dollars to influence races this year have not been required to disclose their donors. 
 
 This month, California's Fair Political Practices Commission forced an Arizona-based group to reveal the source of $11 million it gave for two ballot initiative campaigns. The funds were traced to a Virginia nonprofit that also does not reveal its donors. That hasn't satisfied the commission, which has begun an investigation to uncover the original source. 
 
 Shortly before election day, judges in Idaho and Montana required the disclosure of contributors to two nonprofit organizations that had drawn the attention of state regulators with their political activity. 
 
 "Frankly, if we didn't take a stand on this, we might as well just pack up our campaign disclosure law and send it away," said Idaho Secretary of State Ben Ysursa. "The fact that federal campaign laws are deficient or you've got a deadlocked Federal Election Commission — that doesn't mean the states are powerless." 
 
 Ysursa sued a group called Education Voters of Idaho, which gave more than $200,000 for ads backing three state ballot measures, accusing it of failing to comply with the state's sunshine law. After the court order, the organization revealed it had received money from New York Mayor Michael R. Bloomberg and Albertsons supermarket scion Joseph P. Scott, among others. 
 
 The clashes between state elections officials and advocacy groups are a byproduct of the U.S. Supreme Court's 2010 ruling in Citizens United vs. Federal Election Commission, which lifted the ban on direct political expenditures by corporations. That triggered a surge of election activity by groups incorporated under the tax code's section 501(c)4 as social welfare organizations, which are allowed to engage in issue advocacy. 
 
 At the federal level, political action committees are required to report their contributors, but so far the nonprofits are not. 
 
 The Federal Election Commission, which has six members split evenly between the major parties, is frozen in partisan gridlock on questions regarding nonprofit activity. The Internal Revenue Service said this summer that it had begun examining some of the groups, but had yet to take any public action. And efforts to pass new disclosure laws have so far foundered in Congress. 
 
 But the picture is different in many states, where lawmakers have toughened disclosure rules to require any organization making a political expenditure to report its financial backers. 
 
 Disclosure opponents have systematically challenged the state measures in court, arguing that the Supreme Court has said a group must have politics as its "major purpose" in order to be considered a political committee. 
 
 Advocates for more campaign finance reporting have countered — largely successfully — that the high court has repeatedly endorsed disclosure and has not limited it to political committees. 
 
 "If you look at the federal issue, you would be inclined to throw up your hands," said Derek Cressman, vice president for state operations at Common Cause, which advocates for more transparency. "The progress that some states are making proves that these disclosure issues are problems we can solve." 
 
 Take the case of Americans for Job Security, a Virginia-based nonprofit that has been a serious political player for at least a dozen years, spending millions on ads without disclosing its backers. 
 
 In 2008, the FEC's general counsel concluded the trade group met the definition of a political committee that is required to report its donors, and requested approval to pursue a formal investigation. But the commission deadlocked, and no action was taken. 
 
 Early this month, Americans for Job Security played a role in one of California's most closely watched election-year dramas — unmasked as the source of an $11-million donation to oppose Gov. Jerry Brown's tax increase measure and support another measure intended to curb the ability of unions to raise money for political activity. 
 
 The money had first been routed to an Arizona group called the Center to Protect Patient Rights, which sent it to another nonprofit also based in Arizona called Americans for Responsible Leadership, which in turn gave the money to the conservative Small Business Action Committee in California to run ads about the ballot measures. 
 
 State authorities called it "campaign money laundering." 
 
 Ann Ravel, chairwoman of the Fair Political Practices Commission, said the contribution may have violated a rule implemented in May to prevent donors from anonymously shuttling money through nonprofits with the intention of spending it on California campaigns. If found in violation, the nonprofits involved could face millions of dollars in fines. 
 
 The Small Business Action Committee could also be forced to pay $11 million to the state's general fund if authorities prove it knowingly failed to report the original source of its funds, Ravel said. 
 
 The committee and Americans for Responsible Leadership have denied breaking any rules. 
 
 State Sen. Leland Yee (D-San Francisco) said he planned to introduce legislation that would require more complete disclosure. 
 
 "How can anyone allow organizations of whatever kind to come into this state and not disclose the true source of money?" he said. 
 
 A similar fight is playing out in Montana, where a group called American Tradition Partnership has been locked in a battle with the agency that enforces the state's campaign finance rule. 
 
 In October 2010, Montana's commissioner of political practices concluded that the group's activities, which included sending mailers attacking Democratic and moderate Republican lawmakers, meant it had to file reports as a political committee. ATP sued, challenging the disclosure laws as unconstitutional and arguing that it is an educational group. 
 
 ATP has remained active in state politics, sending out a mock newspaper this fall that featured gubernatorial candidate Steve Bullock, the state's attorney general, in a photo array of sex offenders as part of an article that slammed his handling of the state's sex offender database. 
 
 The legal wrangling between state officials and ATP is ongoing, but has already pulled back the curtain on the group's contributors. Shortly before election day, the state judge hearing the case released a cache of the group's financial documents that state prosecutors had subpoenaed from Wells Fargo. The documents, which the PBS show "Frontline" and the investigative website ProPublica had requested, showed that ATP donors have included nonprofits linked to Republican activists in Colorado, as well as some major GOP donors. 
 
 In Maine, state ethics officials are investigating the National Organization for Marriage, which has refused to release the names of donors that financed its efforts to defeat a 2009 measure to legalize same-sex marriage. 
 
 The nonprofit groups under scrutiny say they are caught between conflicting state and federal regulations. 
 
 John Foster, the Boise-based lobbyist and political consultant behind Education Voters of Idaho, said he set it up as a 501(c)4 because its activities fall squarely within the IRS definition of a social welfare organization. Donors gave money for education reform, not earmarked for political campaigns, he said, so the group should not have to reveal names. 
 
 "We are very proud of our donors, and the prospect of releasing them publicly was never an issue for us," Foster said. "It was always about whether we get to decide who we are, or whether a state regulator gets to decide who we are." 
 
 "The rules are not entirely clear," he added. "This just highlights the continuing need for a realistic, constitutional approach to campaign finance reform in this country." 
 
 matea.gold@latimes.com 
 
 chris.megerian@latimes.com ||||| Obama: $1.123 billion vs. Romney: $1.019 billion. 
 
 That’s the final fundraising tally in the most expensive presidential election ever, according to reports filed Thursday with the Federal Election Commission by the rival campaigns and party committees. 
 
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 reset 2012’s high-end fundraisers 
 
 And that doesn’t include an explosion of late advertising funded by last-minute checks from mega-donors like Las Vegas casino owner Sheldon Adelson and Chicago media mogul Fred Eychaner, whose emergence as political forces may be the enduring legacy of 2012. 
 
 (Also on POLITICO: Adelson gave another $10M to Romney super PAC) 
 
 Adelson and his wife gave $39.7 million to GOP-allied super PACs in the campaign’s final weeks to bring their total disclosed contributions to almost $90 million, while Eychaner gave $2 million, bringing his total to $14 million. 
 
 Thursday’s filings lay bare those donations and other jaw-dropping financial details of the first modern presidential campaign in which donors could give unlimited contributions for political ads and in which both major party candidates declined to participate in a Watergate-era public financing system designed to limit fundraising. The reports also show how the two candidates and their allies navigated the new big-money system using divergent strategies until the bitter end. 
 
 (PHOTOS: 2012 mega-donors) 
 
 President Barack Obama’s campaign relied on smaller donors to fuel a robust ground game and summer advertising seeking to define Republican rival Mitt Romney, and then widened its fundraising advantage as the campaign reached its apex. But it was actually outspent by Romney and the big-donor-funded outside groups that supported him. They banked on larger donations to flood the airwaves in the final weeks to turn late-deciding voters against the incumbent in a backloaded strategy that left them with money in the bank at the end – typically a no-no in presidential politics. 
 
 Between Oct. 18 and Nov. 26, the period covered by Thursday’s filings, Obama’s campaign, combined with a trio of Democratic Party committees devoted to it (the Democratic National Committee and the joint DNC-Obama campaign committees called Obama Victory Fund 2012 and Swing State Victory Fund), raised $111 million, compared to $100 million raised by Romney’s campaign, the Republican National Committee and the joint RNC-Romney campaign Romney Victory. 
 
 POLITICO’s overall fundraising comparison is derived from the totals raised by those committees since the start of 2011. 
 
 (Also on POLITICO: Liberal donors gave at 11th hour) 
 
 But in the final weeks, Romney’s committees outspent Obama’s $292 million to $258 million, according to the reports. And Romney’s spending advantage widened to $337 million to $279 million when taking into consideration the super PACs devoted to the rivals, the pro-Obama Priorities USA Action and the pro-Romney Restore Our Future. Overall, Restore Our Future outraised Priorities $154 million to $79 million. 
 
 Super PACs like those, as well as secretive nonprofit groups – both spurred by the 2010 Citizens United decision and other federal court rulings – allowed extremely wealthy activists to play in presidential and congressional politics like never before. 
 
 And, while liberals rallied late in the cycle to super PACs supporting Obama and his Democratic congressional allies, conservatives led the way with this new type of campaign cash. ||||| Over the last two years, government watchdog groups filed more than a dozen complaints with the Internal Revenue Service seeking inquiries into whether large nonprofit organizations like those founded by the Republican political operative Karl Rove and former Obama administration aides had violated their tax-exempt status by spending tens of millions of dollars on political advertising. 
 
 The I.R.S. never responded. 
 
 During the same period, the agency singled out dozens of Tea Party-inspired groups that had applied for I.R.S. recognition, officials acknowledged on Friday, subjecting them to rounds of detailed questioning about their political activities. None of those groups were big spenders on political advertising; most were local Tea Party organizations with shoestring budgets. 
 
 For the I.R.S.’s bipartisan legion of critics, the agency’s record has underscored its contradictory and seemingly confused response to the fastest-growing corner in the world of unlimited political spending: tax-exempt groups that have paid for at least half a billion dollars in campaign ads during the last two election cycles. 
 
 The I.R.S. has done little to regulate a flood of political spending by larger groups — like Crossroads Grassroots Policy Strategies, co-founded by Mr. Rove, and Priorities USA, with close ties to President Obama — as well as Republican leaders in Congress and other elected officials. And an agency that is supposed to stay as far away from partisan politics as possible has been left in charge — almost by accident — of regulating a huge amount of election spending. 
 
 “We’ve complained about a few big fish and we’ve heard nothing from the I.R.S.,” said Paul S. Ryan, senior counsel at the Campaign Legal Center, which filed many of the complaints with the agency. “We would far rather see scrutiny of these big fish — the groups that spent hundreds of millions of dollars to influence elections — than to see the resources spent on hundreds of small groups that appeared to spend very little on elections.” 
 
 Almost all of the groups in question are organized under 501(c)(4) of the tax code, which regulates nonprofit groups engaged in promoting “social welfare.” At least 16 such organizations spent a million dollars or more on campaign advertising in the 2012 elections. (Crossroads GPS and Priorities USA also run “super PACs” with similar names that spent millions more.) 
 
 But because they purport to be engaged primarily in issue advocacy, not election advocacy, tax-exempt groups are not closely regulated by the Federal Election Commission. That task falls, instead, to the I.R.S., which can take years to investigate problems and is required to do so in strict secrecy. 
 
 Some groups, like Crossroads, filed applications for I.R.S. tax-exempt status, claiming that they would be engaged primarily on research and educational activities but spending the bulk of their money on what appears to be political advertising. Others, like the American Tradition Partnership, operate for years at a stretch without filing federal tax returns, in seeming violation of the law. Many boast of their impact on political campaigns. 
 
 But while a few of the big groups have faced delays in having their tax exemptions recognized by the I.R.S., none appear to have received the intense scrutiny given the Tea Party groups, which were asked dozens of questions about spending on political advertising and other election activities. Of 15 such groups represented by Jay Sekulow, a lawyer with the American Center for Law and Justice, none spent a dollar on broadcast advertising from 2009 through 2012, according to the Campaign Media Analysis Group. 
 
 I.R.S. officials said they had also submitted as many as 200 other groups’ applications to closer examination, but have declined to characterize those groups’ political affiliation. 
 
 Chris Ashby, a lawyer who advises conservative groups, said the I.R.S. might have focused on smaller groups because they seemed less likely to contest the reviews. “The big groups are generally well-advised, lawyered up. Their tax forms are artfully drawn,” Mr. Ashby said. Smaller groups, he suggested, made a better target for the I.R.S. 
 
 “Many of them don’t have counsel,” he said. “They probably aren’t well advised.” 
 
 Unlike candidates and super PACs, which must register quickly with the Federal Election Commission and regularly file financial disclosures, 501(c)(4) groups can operate for years while waiting for the I.R.S. to recognize their tax status. Nor are they required to disclose their donors — one reason they appear to be the preferred vehicle for large, publicly traded corporations that seek to influence elections without identifying themselves.
– The Federal Election Commission is stuck in partisan gridlock—so states are taking nonprofit donor disclosure into their own hands. California this month called on an Arizona group to uncover the source of $11 million used for ballot measure fights; recent court cases in Idaho and Minnesota have forced political organizations to reveal their backers; and Maine is investigating a secretive group opposed to gay marriage. "The fact that federal campaign laws are deficient or you've got a deadlocked Federal Election Commission—that doesn't mean the states are powerless," says Idaho's secretary of state. "Frankly, if we didn't take a stand on this, we might as well just pack up our campaign disclosure law and send it away," he adds. While political action committees are required under federal law to reveal their donors, nonprofits aren't subject to those rules, the Los Angeles Times notes. Meanwhile, Democrats are looking a lot less concerned about super PACs after their successes this time around, and party leaders are already preparing for 2014 and 2016, Politico reports. A secret three-day donor meeting convened just after the election, aiming to trump a big financial advantage on the Republican side.