From the majority opinion:
The First Amendment does not permit laws that force speakers to retain a campaign finance attorney, conduct demographic marketing research, or seek declaratory rulings before discussing the most salient political issues of our day. Prolix laws chill speech for the same reason that vague laws chill speech: People “of common intelligence must necessarily guess at [the law’s] meaning and differ as to its application.” …
As additional rules are created for regulating political speech, any speech arguably within their reach is chilled. Campaign finance regulations now impose “unique and complex rules” on “71 distinct entities.” These entities are subject to separate rules for 33 different types of political speech. The FEC has adopted 568 pages of regulations, 1,278 pages of explanations and justifications for those regulations, and 1,771 advisory opinions since 1975. In fact, after this Court in WRTL [the 2007 Wisconsin Right to Life case] adopted an objective “appeal to vote” test for determining whether a communication was the functional equivalent of express advocacy, the FEC adopted a two-part, 11-factor balancing test to implement WRTL’s ruling.
This regulatory scheme may not be a prior restraint on speech in the strict sense of that term, for prospective speakers are not compelled by law to seek an advisory opinion from the FEC before the speech takes place. As a practical matter, however, given the complexity of the regulations and the deference courts show to administrative determinations, a speaker who wants to avoid threats of criminal liability and the heavy costs of defending against FEC enforcement must ask a governmental agency for prior permission to speak. These onerous restrictions thus function as the equivalent of prior restraint by giving the FEC power analogous to licensing laws implemented in 16th- and 17th-century England, laws and governmental practices of the sort that the First Amendment was drawn to prohibit. Because the FEC’s “business is to censor, there inheres the danger that [it] may well be less responsive than a court — part of an independent branch of government — to the constitutionally protected interests in free expression.” When the FEC issues advisory opinions that prohibit speech, “[m]any persons, rather than undertake the considerable burden(and sometimes risk) of vindicating their rights through case-by-case litigation, will choose simply to abstain from protected speech — harming not only themselves but society as a whole, which is deprived of an uninhibited marketplace of ideas.” Consequently, “the censor’s determination may in practice be final.”
This is precisely what WRTL sought to avoid. WRTL said that First Amendment standards “must eschew ‘the open-ended rough-and-tumble of factors,’ which ‘invit[es] complex argument in a trial court and a virtually inevitable appeal.’” Yet, the FEC has created a regime that allows it to select what political speech is safe for public consumption by applying ambiguous tests. If parties want to avoid litigation and the possibility of civil and criminal penalties, they must either refrain from speaking or ask the FEC to issue an advisory opinion approving of the political speech in question. Government officials pore over each word of a text to see if, in their judgment, it accords with the 11-factor test they have promulgated. This is an unprecedented governmental intervention into the realm of speech.
The ongoing chill upon speech that is beyond all doubt protected makes it necessary in this case to invoke the earlier precedents that a statute which chills speech can and must be invalidated where its facial invalidity has been demonstrated.