This AP story on a report by the left-leaning Center for Public Integrity, documents the rise of "527 groups", which are increasingly becoming an alternative to soft-money donations. The report documents how the Democratic Party is strongly outpacing the GOP in utilization of these groups. The story is quick to point out that the disparity may not be as great as it appears at first blush, because
The existence of these other tax exempt groups makes it difficult to determine whether Democrats or Republicans are spending the most money. The reason is that non-527 tax-exempt organizations do not disclose details about their fund raising and spending.
A graphic on the groups 527 gateway page, however, notes that just one component, labor unions, have spent more than all GOP-leaning PACS, and they are not the biggest spending left-leaning group (Democratic Party candidates and supporters are understandably strongly supportive of the Democratic Party).
The CPI article accompanying the report contained an interesting (if wrong) statement by a supporter of campaign finance reform.
People associated with labor groups, environment groups, abortion rights groups are all by definition of one mind on their issue, which is not true of a shareholder who invests in GM," said Trevor Potter, a former FEC commissioner who is part of the legal team defending the new federal campaign law before the Supreme Court.
If that was the case, how does one explain the fact that about 30% of union households vote Republican? (Greater than 85% of all union spending is spent on Democratic Party candidates and issues.)
It is also pointed out, in the same article, that labor groups spend more than six times as much as corporations through 527 spending. Corporations donate a lot through other methods, but they are still outspent (by a wide margin) by unions and union affiliates. The GOP's edge in fundraising comes through donations of less than $200, something the Dems have not managed to equal, despite their "party of the people" claims.