Washington (CNN) -- In rural southern Virginia, 14-term Democratic Rep. Rick Boucher says he's never had an election enemy quite like the ones he's facing this year. Its not his opponent, but instead it's what he calls a "shadowy" group that is funding television ads against him. "Rick Boucher is trying to deceive you ... Boucher has failed to protect our jobs. Now it's time Rick Boucher loses his," the ad's narrator says. The 30-second commercial was paid for by Americans for Job Security, a conservative-leaning group which, according to the nonpartisan watchdog group OpenSecrets.org, has spent nearly $8 million against Democratic candidates nationwide.
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Political groups operate outside parties and do not have to reveal members or donors
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It's difficult for voters to figure out who is behind messaging, watchdog group says
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President Obama has attacked groups for spending millions without disclosing donors
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Democratic-leaning groups are also cloaking their funding sources, however
And Democrats have smaller outside groups aimed at getting @placeholder voters to the polls.