WASHINGTON -- 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.

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  • Birth Certificate -- "Born In The USA"

    <a href="http://www.huffingtonpost.com/2011/04/27/obama-birth-certificate-r_n_854248.html" target="_hplink"><strong>(April 27, 2011) --</strong></a> The White House <a href="http://www.whitehouse.gov/blog/2011/04/27/president-obamas-long-form-birth-certificate" target="_hplink">released</a> President Barack Obama's "long form" birth certificate, adding documentation to a longstanding discussion over his ability to serve as commander in chief. "We do not have time for this kind of silliness," Obama said. "We have better stuff to do. I have got better stuff to do. We have got big problems to solve." (JEWEL SAMAD/AFP/Getty Images)

  • Osama Bin Laden Killed -- "Tonight, Tonight"

    <a href="http://www.huffingtonpost.com/2011/05/01/osama-bin-laden-dead-killed_n_856091.html" target="_hplink"><strong>(May 1, 2011)</strong></a> -- In a televised address to the nation, Obama announces that Osama bin Laden is dead. His death was the result of a U.S. operation launched today in Abbottabad, Pakistan, against a compound where bin Laden was believed to be hiding. "[T]oday's achievement is a testament to the greatness of our country and the determination of the American people," Obama proclaimed. (Photo by Pete Souza/The White House via Getty Images)

  • Debt Ceiling Deal -- "Gold On The Ceiling"

    <a href="http://www.huffingtonpost.com/2011/08/02/obama-debt-ceiling-deal-jobs_n_916285.html" target="_hplink"><strong>(Aug. 2, 2011) --</strong></a> After the Senate passed a bill to raise the debt limit, Obama pleaded with Congress to shift their attention to jobs. "I will urge them to immediately take some steps -- bipartisan, common-sense steps -- that will make a difference; that will create a climate where businesses can hire, where folks have more money in their pockets to spend, where people who are out of work can find good jobs," he said. (Photo by Brendan Smialowski/Getty Images)

  • Don't Ask Don't Tell -- "Don't Stop Believin'"

    <a href="http://www.huffingtonpost.com/2011/09/20/barack-obama-dont-ask-dont-tell-repeal-statement_n_971662.html" target="_hplink"><strong>(Sept. 20, 2011) --</strong></a> As the ban on gays serving in the military came to an end, Obama hailed the fresh start, celebrating the fact that "patriotic Americans in uniform will no longer have to lie about who they are in order to serve the country they love." (Photo by Brendan Hoffman/Getty Images)

  • Iraq War To End -- "Homeward Bound"

    <a href="http://www.huffingtonpost.com/2011/10/21/obama-iraq-troop-withdrawal_n_1024108.html" target="_hplink"><strong>(Oct. 21, 2011) --</strong></a> Obama announced that all U.S. troops will be out of Iraq by 2011, fulfilling a promise that dated back to his campaign. "As a candidate for president, I pledged to bring the war in Iraq to a responsible end," Obama said. "So today I can report that, as promised, the rest of our troops in Iraq will come home by the end of the year." (Photo credit should read JIM WATSON/AFP/Getty Images)

  • Singing Al Green's "Let's Stay Together"

    <a href="http://www.huffingtonpost.com/2012/01/20/obama-al-green-apollo-theater_n_1218070.html" target="_hplink"><strong>(Jan. 20, 2012) --</strong></a> During a fundraiser at Harlem's historic Apollo Theater, Obama delivered a memorable musical message to his donors. With Rev. Al Green in attendance, Obama sang part of Green's hit song "Let's Stay Together," drawing strong applause from the crowd.

  • Singing Robert Johnson's "Sweet Home Chicago"

    <a href="http://www.huffingtonpost.com/2012/02/21/obama-sings-sweet-home-chicago_n_1292576.html" target="_hplink"><strong>(Feb. 21, 2012) --</strong></a> Days after his Al Green rendition, Obama flexed his vocal chords again with a hometown favorite. The East Room of the White House had its blues fix filled when the president started swinging "Sweet Home Chicago."

  • Gay Marriage -- "Can't Fight This Feeling"

    <a href="http://www.huffingtonpost.com/2012/05/09/obama-gay-marriage_n_1503245.html" target="_hplink"><strong>(May 9, 2012) --</strong></a> In a sit-down interview with ABC's Robin Roberts, Obama explained his evolution on the issue, affirming his support for gay marriage. "[A]t a certain point I've just concluded that for me personally it is important for me to go ahead and affirm that I think same sex couples should be able to get married," he said.

  • Immigration -- "With Arms Wide Open"

    <a href="http://www.huffingtonpost.com/2012/06/15/obama-immigration-order-deportation-dream-act_n_1599658.html " target="_hplink"><strong>(June 15, 2012) --</strong></a> The Obama administration addressed America's immigration issue, announcing that it will halt deportations and grant work permits to young individuals eligible for Dream-Act benefits. "They pledge allegiance to our flag," Obama said. "They are Americans in their hearts, in their minds, in every single way but one: on paper."(Photo by Alex Wong/Getty Images)

  • Health Care Reform -- "Beautiful Day"

    <a href="http://www.huffingtonpost.com/2012/06/28/supreme-court-health-care-decision_n_1585131.html" target="_hplink"><strong>(June 28, 2012) --</strong></a> After weeks of speculation that Obama's signature piece of legislation could be overturned, the Supreme Court ruled that the Affordable Care Act's individual mandate is constitutional. "It should be pretty clear that I didn't do this because it's good politics," <a href="http://www.huffingtonpost.com/2012/06/28/obama-health-care-ruling_n_1632953.html" target="_hplink">Obama said</a>. "I did it because it's good for the country." (Photo by Alex Wong/Getty Images)