Updated

Organized labor spends about four times as much on politics and lobbying as generally thought, according to a Wall Street Journal analysis, a finding that shines a light on an aspect of labor's political activity that has often been overlooked.

Previous estimates have focused on labor unions' filings with federal election officials, which chronicle contributions made directly to federal candidates and union spending in support of candidates for Congress and the White House.

But unions spend far more money on a wider range of political activities, including supporting state and local candidates and deploying what has long been seen as the unions' most potent political weapon: persuading members to vote as unions want them to.

The new figures come from a little-known set of annual reports to the Labor Department in which local unions, their national parents and labor federations have been required to detail their spending on politics and lobbying since 2005.

This kind of spending, which is on the rise, has enabled the largest unions to maintain and in some cases increase their clout in Washington and state capitals, even though unionized workers make up a declining share of the workforce. The result is that labor could be a stronger counterweight than commonly realized to "super PACs" that today raise millions from wealthy donors, in many cases to support Republican candidates and causes.

The hours spent by union employees working on political matters were equivalent in 2010 to a shadow army much larger than President Barack Obama's current re-election staff, data analyzed by the Journal show.

The usual measure of unions' clout encompasses chiefly what they spend supporting federal candidates through their political-action committees, which are funded with voluntary contributions, and lobbying Washington, which is a cost borne by the unions' own coffers.

These kinds of spending, which unions report to the Federal Election Commission and to Congress, totaled $1.1 billion from 2005 through 2011, according to the nonpartisan Center for Responsive Politics.

The unions' reports to the Labor Department capture an additional $3.3 billion that unions spent over the same period on political activity.

The costs reported to the Labor Department range from polling fees, to money spent persuading union members to vote a certain way, to bratwursts to feed Wisconsin workers protesting at the state capitol last year. Much of this kind of spending comes not from members' contributions to a PAC but directly from unions' dues-funded coffers. There is no requirement that unions report all of this kind of spending to the Federal Election Commission, or FEC.

"We have always known that much of [unions'] influence comes from their political mobilization, but we have never been able to put a number on it," said Bob Biersack, a longtime FEC official who is now with the Center for Responsive Politics. "They are a human force in the political process, but a lot of that falls outside the kind of spending that needs to be disclosed to the FEC."

Laurence E. Gold, counsel to the AFL-CIO, said the Labor Department reports show that "unions by law are the most transparent institutions about their electoral spending."

Comparisons with corporate political spending aren't easy to make. Some corporate political spending, such as donations to the U.S. Chamber of Commerce's political wing, doesn't need to be disclosed. What does have to be disclosed can't be found in a single database or two, as is the case with unions.

Another difference is that companies use their political money differently than unions do, spending a far larger share of it on lobbying, while not undertaking anything equivalent to unions' drives to persuade members to vote as the leadership dictates.

Corporations and their employees also tend to spread their donations fairly evenly between the two major parties, unlike unions, which overwhelmingly assist Democrats. In 2008, Democrats received 55% of the $2 billion contributed by corporate PACs and company employees, according to the Center for Responsive Politics. Labor unions were responsible for $75 million in political donations, with 92% going to Democrats.

Unlike super PACs, which cannot directly support campaigns, corporate PACs give money from employees to candidates.

The traditional measure of unions' political spending-reports filed with the FEC-undercounts the effort unions pour into politics because the FEC reports are mostly based on donations unions make to individual candidates from their PACs, as well as spending on campaign advertisements.

The limited nature of the disclosure grew out of a 1948 Supreme Court decision that, in the particular matter then before the court, spared unions and companies from disclosing the costs of political communications with their members or employees.

Unions spend millions of dollars yearly paying teams of political hands to contact members, educating them about election issues and trying to make sure they vote for union-endorsed candidates.

Such activities are central to unions' political power: The proportion of members who vote as the leadership prefers has ranged from 68% to 74% over the past decade at AFL-CIO-affiliated unions, according to statistics from the labor federation.

But much of unions' spending on this effort-involving internal communication with members-doesn't have to be reported to the FEC. It does, however, have to be reported to the Labor Department.

The reports to the Labor Department also take in a broader swath of political activity by including spending on campaigns that aren't federal, such as for state legislatures and governors.

The Labor Department data show about 3,000 local unions, their national parents and labor federations reporting at least some spending on politics and lobbying each year since 2005. Just 35 unions accounted for more than half of it, according to the Journal's analysis.

The top political spender, counting both what is reported to the Labor Department and what is reported to the FEC, was the Service Employees International Union. Unlike most unions, the SEIU has seen its membership grow-to 1.9 million last year from 1.5 million in 2005. It reported spending $150 million on politics and lobbying in 2009 and 2010, up from $62 million in 2005 and 2006.

"The growth of SEIU political spending reflects the commitment of SEIU members to knock on doors, make phone calls and voluntarily contribute an average of $7 per month to ensure the voice of working families and the 99% is heard at the ballot box," said its national political director, Brandon Davis.

About 54% of the political spending that unions report to the Labor Department consists of campaign donations to state and local candidates plus fees paid to consultants, attorneys and service providers, such as the U.S. Postal Service to deliver political mailings.

The remainder represents portions of the salaries of union officials and employees attributable to political and lobbying activities. In 2010, politics and lobbying accounted for at least 50% of the hours worked by 1,996 union employees; 940 employees spent all of their time on politics, the unions reported.

The reported hours worked in 2010 were equivalent to 3,242 full-time operatives with a payroll of $214 million, according to the Journal's analysis.

Many unions report on a fiscal-year basis, with the result that for some, the 2011 reports include spending from the end of 2010 and the beginning of 2011.

Among the unions and labor federations, the five largest now devote greater portions of their budgets to politics and elections than they did in 2005, when the Labor Department first began tracking such spending. Politics and lobbying accounted for 13% of their total spending during the 2005-2006 election season. By the 2009-2010 cycle, this had risen to 16%.

Labor's increasing focus on politics has helped make it a force despite the long-term decline in the unionized workforce. Only about one in eight U.S. workers now belongs to a labor union, data from the Bureau of Labor Statistics show, vs. about one in six 25 years ago. But union members turn out for elections. According to the AFL-CIO, about one in four voters this November will come from a union household.

Unions confronting threats are among the biggest political spenders. The American Federation of State, County and Municipal Employees-which lost 77,000, or about 5%, of its members in 2010 and 2011-has faced job cuts by cash-strapped local and state governments as well as challenges to bargaining rights from governors, such as Wisconsin's Scott Walker.

Faced with challenges such as these, the union's national headquarters boosted its spending on politics and lobbying to $133 million in the 2009 and 2010 election season, nearly twice the $75 million it spent in the 2005 and 2006 cycle.

"It makes sense that our political spending has ramped up over the last year and a half as our members have come under attack like never before," said the union's former political director, Larry Scanlon. He said it spends about two-thirds of its political budget on state and local politics.

Such spending doesn't ensure success, as seen in the recent failure of a union-backed drive to recall Mr. Walker from office. A push for federal legislation to make it easier to unionize workforces also fell short, early in President Obama's term. Unions then failed in an attempt to deny renomination to a Democratic senator who had opposed the bill, Blanche Lincoln of Arkansas. (She won her primary but lost in the general election to Republican Rep. John Boozman.)

The AFL-CIO has been hit hard by the changing economy and losses of manufacturing jobs. Membership of unions that belong to the federation fell to 11.6 million in 2011 from 13.7 million in 2005.

But political spending by the AFL-CIO headquarters and its affiliated unions climbed to $608 million in the 2009 and 2010 election season from $452 million in 2005 and 2006. They spent $316 million in 2011, a nonelection year, amid the fight with Mr. Walker in Wisconsin.

Lyle Balistreri, the president of an AFL-CIO affiliate in Milwaukee, said unions spent money feeding thousands of union members who took part in weeks of protests against Mr. Walker. "I don't know how many bratwursts were cooked up there to feed those folks for weeks and weeks and weeks," Mr. Balistreri said in an interview during the protests.

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