(CNN) - Democrats, poised to be dealt heavy losses in November's midterm elections, are getting some help from a union ally.
The AFL-CIO is trying to turn out some of its 11.5 million members–the majority of whom are Democrats–by hitting 3.5 million them this week with flyers attacking Republican candidates running in House, Senate and gubernatorial races.
The massive union is targeting candidates in 40 congressional districts, 15 Senate races and 11 gubernatorial contests. The organization mailed nearly 4.5 million pieces in the last two weeks.
"We have been testing and refining the mail program here for decades, and have found it's much more effective among union members than the general public," AFL-CIO Political Communication Director Eddie Vale said in a statement. "The reason being that they see it as a communication from a trusted source, their union, that they want to read, rather than random piece of mail like the general public sees it."
In Connecticut, the mailer targeting GOP Senate candidate Linda McMahon, the former CEO of World Wrestling Entertainment, depicts a masked wrestler flying face down onto a group of adults standing inside of a wrestling ring. The boldface text reads: "Don't let Linda McMahon put the smack down on Connecticut workers."
In California, where former eBay CEO Meg Whitman is the Republican nominee for governor, the mailer asks: "Why would a billionaire CEO like Meg Whitman, who didn't vote for 28 years, suddenly spend over $150 million to become governor?"
Vale said the group's direct mail efforts will continue through Election Day.