The SEIU alone also plans to unleash 100,00o of its purple-shirted goons to campaign for Democrats.

(NY Times) — As the A.F.L.-C.I.O. prepares to endorse President Obama on Tuesday, labor leaders say they will mount their biggest campaign effort, with far more union members than ever before — at least 400,000, they say — knocking on voters’ doors to counter the well-endowed “super PACs” backing Republicans.

The same Supreme Court ruling in 2010 that set the stage for these political action committees to accept unlimited donations also allowed unions to send their foot soldiers to visit not just union members at home, but also voters who do not belong to unions — a move expected to increase labor’s political clout significantly in this year’s elections.

With numerous super PACs expected to broadcast a flood of TV spots in support of the Republican nominee, the Obama campaign is looking to organized labor to play a major role in offsetting that. Labor leaders say they expect unions to spend $400 million this year on national, state and local elections — including $100 million by the American Federation of State, County and Municipal Employees — but they say their ground troops, not money, is labor’s signal contribution.

The Service Employees International Union, with two million members, aims to mobilize 100,000 of its members this year — twice as many as in 2008 — to make phone calls and knock on doors.