Last May Rep. Dave Reichert, R-Wash., raised campaign cash at a reception at the offices of the National Association of Realtors and around the same time, the group's PAC sent his campaign a check for $4,000.

Four months later, in September, the PAC started spending big, but this time on independent expenditures. Three hundred thousand dollars for a campaign ad. Forty-six thousand dollars on Internet ads. By mid-October, the group had spent more than $576,000 in support of Reichert.

When groups make independent expenditures to support or oppose a candidacy, they are not supposed to coordinate in ...