Democrats' self-imposed ban on corporate donations has made it tough to raise cash for the Democratic National Convention, and their hope that unions would step in to fill the void appears to have hit a snag, the Wall Street Journal reports.

Wary of their budgets and upset that the convention will be hosted in right-to-work North Carolina, organized labor won't be giving Democrats the money they're requesting for the Charlotte festivities, union officials told the paper. Some unions, including UNITE HERE, the large service workers union, will not contribute to the convention at all.

Of course, donating money to the convention would pull dollars away from other political causes that unions have a stake in. A spokesman for the International Brotherhood of Electrical Workers told the Journal that it has more pressing priorities than Charlotte. "Registration drives, get-out-the-vote drives and leafleting -- that's where we can make our best contribution," he said.

Of the $60.5 million Democrats spent on the convention in Denver in 2008, about $8.6 million of it came from unions, according to the paper.

Bloomberg first reported last week that Democrats were asking unions to kick money in for the convention due to a funding shortfall. Convention organizers had given a tour of the Charlotte site to several union officials, including representatives with the AFL-CIO, the Teamsters and the United Auto Workers, before asking for financial support, according to Bloomberg.

Some Democrats have asked party leaders to lift the ban on corporate money, though the Obama campaign has said it won't change the policy.

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