The American Federation of State, County and Municipal Employees is now the biggest outside spender of the 2010 elections, thanks to an 11th-hour effort to boost Democrats that has vaulted the public-sector union ahead of the U.S. Chamber of Commerce, the AFL-CIO and a flock of new Republican groups in campaign spending.

The 1.6 million-member AFSCME is spending a total of $87.5 million on the elections after tapping into a $16 million emergency account to help fortify the Democrats' hold on Congress. Last week, AFSCME dug deeper, taking out a $2 million loan to fund its push. The group is spending money on television advertisements, phone calls, campaign mailings and other political efforts, helped by a Supreme Court decision that loosened restrictions on campaign spending.

"We're the big dog," said Larry Scanlon, the head of AFSCME's political operations. "But we don't like to brag."

The 2010 election could be pivotal for public-sector unions, whose clout helped shield members from the worst of the economic downturn. In the 2009 stimulus and other legislation, Democratic lawmakers sent more than $160 billion in federal cash to states, aimed in large part at preventing public-sector layoffs. If Republicans running under the banner of limited government win in November, they aren't likely to support extending such aid to states.

Newly elected conservatives will also likely push to clip the political power of public-sector unions. For years, conservatives have argued such unions have an outsize influence in picking the elected officials who are, in effect, their bosses, putting them in a strong position to push for more jobs, and thus more political clout.

Some critics say public-sector unions are funded by what is essentially taxpayer cash, since member salaries, and therefore union dues, come directly from state budgets.

"Public-sector unions have a guaranteed source of revenue—you and me as taxpayers," said Glenn Spencer, executive director of the Workforce Freedom Initiative at the Chamber of Commerce.

Gregory King, a spokesman for AFSCME, said conservatives make too much of the issue, especially the link to taxpayers. Based on their logic, "the government is funding the movie industry every time AFSCME members go out to the movies," he said.

The union is spending heavily this year because "a lot of people are attacking public-sector workers as the problem," said AFSCME President Gerald McEntee. "We're spending big. And we're damn happy it's big. And our members are damn happy it's big—it's their money," he said.

Continue reading at The Wall Street Journal