Michael Barone‘s latest article for the Washington Examiner discusses the impact of public-sector union spending on this year’s campaigns:

Who is the largest single political contributor in the 2010 campaign cycle? You can be pardoned if you answer, erroneously, that it’s some new conservative group organized by Karl Rove. That’s campaign spin by the Obama Democrats, obediently relayed by certain elements of the so-called mainstream media.

The real answer is AFSCME, the American Federation of State, County and Municipal Employees. The union’s president, Gerald McEntee, reports proudly that AFSCME will be contributing $87.5 million in this cycle, entirely or almost entirely to Democrats. “We’re spending big,” he told the Wall Street Journal. “And we’re damn happy it’s big.”

The mainstream press hasn’t shown much interest in reporting on unions’ campaign spending, which amounted to some $400 million in the 2008 cycle. And it hasn’t seen fit to run long investigative stories on why public employee unions — the large majority of which work for state and local governments — contribute so much more to campaigns for federal office.

Nor has it denounced the Supreme Court’s Citizens United decision last January allowing unions to spend members’ dues on politics without their permission and without disclosure.