With respect to campaign financing; disclosure chills speech and speech without disclosure risks corruption. At issue is whether to uphold the D's rule requiring corporations and labor organizations to disclose only those donations 'made for the purpose of furthering electioneering communications' or whether the Bipartisan Campaign Reform Act (BCRA) requires disclosure of all donations irrespective of donative purpose. P-a member of the United States House of Representatives-challenged this rule under the familiar Chevron and State Farm frameworks. The BCRA recognizes and regulates a new category of political advertising called 'electioneering communications,' defined as communications that 'refer to a clearly identified candidate' 'made within' sixty days of a general election or thirty days of a primary election. Any person making an expenditure (referred to as a 'disbursement') totaling more than $10,000 was to disclose 'all persons sharing the costs of the disbursement.' The BCRA altogether banned corporations and unions from using their general treasuries to fund electioneering communications. D promulgated several rules to enforce the various reforms. D promulgated a rule enforcing BCRA's ban on corporate and union expenditures for electioneering communications. D also promulgated a rule to enforce BCRA's requirement for disclosure of 'the names and addresses of all contributors who contributed an aggregate amount of $1,000 or more to the person making the disbursement.' Thus, corporations and unions could not fund electioneering communications out of their general treasuries, and with certain exceptions, persons making disbursements for electioneering communications had to disclose the names of anyone who donated $1,000 or more to them. In FEC v. Wisconsin Right to Life, the Court held corporations and unions could not be barred from electioneering communications unless they are 'the functional equivalent of express advocacy.' An ad is only the functional equivalent of express advocacy, the Court said, when it 'is susceptible of no reasonable interpretation other than as an appeal to vote for or against a specific candidate.' D published a Notice of Proposed Rulemaking (NPRM) and requested comments on proposed rules that 'would implement the Supreme Court's decision in Wisconsin Right to Life.' D adopted a middle path. Corporations and unions would not be altogether exempted, but neither would they be required to disclose every donation totaling $1,000 or more. They would be required to disclose all donations totaling $1,000 or more that were 'made for the purpose of furthering electioneering communications.' This new 'purpose requirement' set corporate and union electioneering communications apart from communications funded by other persons, who were still required to disclose all donations regardless of purpose. P challenged D's new purpose requirement and persuaded the district court that it violated BCRA's text. That decision was appealed to and reversed by a panel of this court. On remand, the district court concluded that D's rule failed at both the Chevron Step Two and arbitrary and capricious stages. The Center for Individual Freedom (P) filed its notice of appeal shortly thereafter.