Amid the sound and fury of the Battle of the Shutdown, the black-robed Justices of the U.S. Supreme Court quietly heard oral arguments Tuesday on what could produce a landmark ruling in the history of the First Amendment. The case is McCutcheon v. Federal Election Commission, which summons the Court to review the fundamental principle of the campaign finance reform movement - the mere appearance of corruption between a candidate and a donor is sufficient ground under the Constitution to limit freedom of political speech. Apart from this principle, the Court could not have approved in its 1976 Buckley v. Valeo decision the arbitrary ceiling placed by the Federal Election Commission on an individual's aggregate federal campaign donations in one campaign cycle. It was $48,600 in the 2012 cycle.

Alabama businessman Shaun McCutcheon challenged the ceiling because, as George Will explained in a recent column, “the illogic of aggregate limits is glaring: He could give $2,600 -- which Congress considers innocuous -- to 18 candidates without an appearance of corruption, but $2,600 to the 19th would somehow trigger the appearance.” Nobody knows exactly how the bureaucrats at the FEC, members of Congress or the Justices who decided Buckley determined that the unmistakable appearance of corruption suddenly appears at any particular dollar threshold. They cannot know because neither the bureaucrats nor the congressmen nor the justices know how they did it.

Since the Court has long said that the appearance of corruption must be established in order to limit political speech, the FEC’s ceiling must be vacated. Otherwise, the FEC abrogates to itself an unaccountable power to revise the First Amendment through regulatory fiat. Such a result pleases those in Congress, the campaign finance reform movement and the legal profession, all of whom applaud the FEC, but it horrifies every true friend of civil liberties.

They are properly horrified for two reasons: First, providing financial support to a favored political candidate or cause is as intrinsically an act of political speech as writing a letter to the editor, posting a yard sign or delivering a speech in a candidate forum. This is why the debate between proponents and opponents of campaign finance regulations such as contribution limits has always been at its core about whether it is ever proper for Congress to determine how much political speech is too much. The Constitution rather explicitly answers that question in the First Amendment: “Congress shall make no law respecting … the freedom of speech …”

First Amendment author James Madison’s wisdom is on vivid display here. He knew incumbent congressmen would face an unresolvable conflict between their constitutional obligation to protect political speech and the practical temptation to defend their incumbency by limiting the political speech of challengers. He sought to keep the obligation while removing the temptation. So should the justices in deciding McCutcheon.