ANNAPOLIS, Md. (AP) -- The Democratic Governors Association, headed by Maryland Gov. Martin O'Malley, is making a push for donations to try to oust Wisconsin Gov. Scott Walker in a recall election.

The DGA sent out an email to donors on Wednesday seeking donations to put advertisements on the air and to help encourage voters to go to the polls on June 5.

Mark Giangreco, a spokesman for the DGA, is asking for donations of $3 or more.

Walker, a Republican, faces Milwaukee Mayor Tom Barrett, a Democrat, in a recall election that is only the third time in the nation's history that a governor has stood for recall. The recall was prompted by Walker's successful push to end nearly all collective bargaining rights for most state workers.