Recently, we noted that McCain-Fiengold dropped a new bill to regulate 527 groups. 501(c) groups have also grown concerned with the bill - because they also engage in political advocacy and get-out-the-vote drives. They are afraid that this will serve as a starting point for Congress, leading to further regulation down the road. This is especially true if donors shift their money to 501(c)s in an attempt to circumvent new contribution limits on 527s. Check out this article in the Chicago Tribune.