As solicitor general of the United States, Elena Kagan argued in front of the Supreme Court that the federal government had the constitutional authority to ban certain political pamphlets. She also strongly implied that some political books, if they were partisan enough, could also be censored.

Kagan's extraordinary claims emerged during the second oral argument of Citizens United v. Federal Election Commission, the campaign finance case made famous by President Barack Obama when he publicly excoriated the justices for their ruling during his State of the Union address. The president alleged that Citizens United would allow corporations to subvert the political process with their economic power. In fact, the case concerns the fundamental political liberties of all citizens. The true stakes were dramatically revealed in the two rounds of oral argument heard by the Court.

In the first argument before the Court, on March 24, 2009, Kagan's deputy, Malcolm L. Stewart, represented the government by arguing for the constitutionality of a statute prohibiting corporations and unions from spending funds from their general treasuries to advocate the election or defeat of political candidates. The justices subjected Stewart to a series of stark hypothetical situations testing the extent of the censorship power that the Obama Administration viewed as constitutionally permissible.

For example, Stewart was asked by Chief Justice John Roberts what would happen if a corporation were to publish a 500-page book discussing the American political system which concluded with a single sentence endorsing a particular candidate. Kagan's deputy answered that such an endorsement would constitute "express advocacy" and therefore the corporation could only fund the publication of the book through a political action committee. "And if they didn't, you could ban it?" asked the chief justice. "If they didn't, we could prohibit publication of the book," Stewart replied.

Even the most liberal justices, usually the most willing to curtail political free speech, seemed a little troubled. Justice David Souter asked what would happen if a labor union paid an author to write a book advocating the election of a particular candidate and then submitted the manuscript to Random House, which then agreed to publish it. The deputy solicitor general replied that he was unsure whether there would be a basis for suppressing such a book, but clearly stated that "the labor union's conduct would be prohibited."

Later, the argument turned to other forms of media that the government would have the right to censor. The implications of the administration's position were so enormous that Justice Antonin Scalia seemed almost incredulous. He sarcastically interrupted to say "I'm a little disoriented here, Mr. Stewart. We are dealing with a constitutional provision, are we not; the one that I remember which says Congress shall make no law abridging the freedom of the press? That's what we're interpreting here?" With no apparent irony, Stewart replied, "That's correct."

The justices were apparently concerned by what they heard, requesting an unusual second oral argument in the case, on September 9, 2009. This time, Kagan went to the Supreme Court herself. Justice Ruth Bader Ginsburg got right to the point by asking Kagan whether it was still the government's position that Congress could ban TV, radio, and newspaper ads, and even campaign biographies under the rubric of campaign finance reform. "The government's answer has changed," Kagan replied, which sparked laughter in the courtroom. Given the skeptical questioning at the prior hearing, Kagan seems to have made the tactical decision to back off from her office's initial claims and opted to craft a less controversial way of getting the justices to accept significant restrictions on free speech. She assured the Court that she took their prior reactions and hypotheticals "very seriously" and that the Obama Administration reconsidered its position. Perhaps this is an example of her reputed pragmatism and interest in building coalitions. In any event, her attempted finesse did not stand up so well under cross-examination.

Kagan conceded that although the statute in question did cover "full length books" it would be subject to "quite good" challenges if it was ever so applied in practice. Moreover, she pointed out that the Federal Election Commission never enforced the law with respect to books, implying that citizens should not worry about being prosecuted. Chief Justice Roberts immediately seized on this, saying "We don't put our First Amendment rights in the hands of FEC bureaucrats." He then asked whether the statute could be used to ban a pamphlet. Such a publication, Kagan admitted, would be different; "a pamphlet is pretty classic electioneering" and could be constitutionally prohibited. She tried to reassure the justices that a book containing hundreds of pages could not be banned just because the last sentence endorsed a candidate, as her deputy had claimed a few months earlier. However, she strongly implied that if the book engaged in "express advocacy" as a whole, it could be banned. Her position would seem to require the FEC to define the differences between books and pamphlets and decide how many sentences in a book are necessary to qualify as "express advocacy." Kagan never addressed whether it was desirable for FEC staffers to become either book reviewers or a de facto national censorship committee. Ultimately, the Court ruled against Kagan by a 5-4 margin.

Many questions remain unanswered about Kagan's comfort with banning political publications and limiting free expression in other media. She might say that her own views on these issues are private and that she was merely advocating for her client in this case. However, it is interesting to note that in nominating Kagan, President Obama went out of his way to praise her defence of ordinary citizens against "unscrupulous corporations," citing her work on Citizens United in particular. "Despite long odds of success, with most legal analysts believing the government was unlikely to prevail in this case, Elena still chose it as her very first case to argue before the Court," Obama declared.

Yet Obama and Kagan both ignored the fact that not all corporations that advocate for candidates are big and "unscrupulous." Most are sole proprietorships of small businesses, and many are non-profits, as was the plaintiff in Citizens United.

As the Senate considers her nomination this week, they ought to ask her the following:

• If a citizen who is the sole owner of a corporation that operates a bakery wants to use his business funds to put a candidate's poster in his storefront window, can that be banned under the Constitution?

• If a group of like-minded citizens form a corporation for the purpose of advocating for candidates in whom they believe, can that corporation constitutionally be prevented from spending money?

• Is it constitutional for the FEC to review political books for content and ban them if they run afoul of a campaign finance law?

• Is it constitutional for media companies to publish content advocating for political candidates? If so, why should they be different from other companies under the Constitution?

• If a corporation or labor union produces a pamphlet with its own funds advocating the election of a candidate, can that document be banned under the Constitution?

The answers would reveal a lot about what kind of justice Kagan might be and how she reconciles her views with the First Amendment. Perhaps more importantly, it would be an opportunity for the public to see what is truly at stake when the government wants to restrict an individual or corporation's ability to support the candidates of its choice.

Daniel Shuchman is a New York money manager and a member of the Board of Directors of the Foundation for Individual Rights in Education. He has written for The Wall Street Journal and The Harvard Journal of Law and Public Policy.