Updated

Labor unions plan to send out more than 300,000 volunteers later this month to canvass voters to support President Barack Obama's re-election.

The effort begins on Aug. 25, when activists fan out across 27 states during a national "day of action."

AFL-CIO President Richard Trumka says a record 400,000 union-based volunteers will be knocking on doors and talking to voters in all 50 states later this year.

For the first time, unions can use their funds to target non-union households as well as those with family members in a union. That change comes as a result of the Supreme Court's landmark campaign finance decision in Citizens United.

Roughly two-thirds of voters in union households backed Obama in 2008.