On March 24, 2009, Deputy Solicitor General Malcolm Stewart told the U.S. Supreme Court that the federal government had the lawful power to ban books if those books happened to mention the name of a candidate for federal office and were published in the run-up to the federal election in which that candidate was competing.

"It's a 500-page book, and at the end it says, so vote for X, the government could ban that?" asked an incredulous Chief Justice John Roberts. Yes, the deputy solicitor general conceded, according to the government's theory of the present case, the government could indeed ban that book. "We could prohibit the publication of the book using the corporate treasury funds," Stewart said.

At issue before the Supreme Court that morning was a little dispute known as Citizens United v. Federal Election Commission. Perhaps you've heard something about it. If you haven't, you certainly will this week as the Democratic National Convention gets rolling in Philadelphia. Attacking Citizens United has become something of a pastime among certain types of liberal Democrats. Former MSNBC personality Keith Olbermann, for instance, once famously claimed that Citizens United "might actually have more dire implications than Dred Scott," the 1857 case which helped trigger the Civil War.

Thankfully, the 2016 Democratic Party Platform does not go full Olbermann. But it does complain that "Citizens United has fundamentally transformed our democracy" while calling for the case to be overturned by either constitutional amendment or by a future Supreme Court majority. Hillary Clinton, meanwhile, has repeatedly vowed to impose an anti-Citizens United litmus test on all of her judicial nominees.

Needless to say, you won't hear much at the DNC this week about how the federal government once tried to claim the power to ban books in its losing Citizens United argument. Nor will you hear much about the fact that the ACLU?nobody's idea of a conservative outfit?actively sided with Citizens United and filed a brief that opposed the government's censorious position (Floyd Abrams, the legendary First Amendment lawyer who previously battled the Nixon administration in the 1971 Pentagon Papers case, likewise came down on the side of Citizens United).

So ignore Hillary Clinton and ignore the DNC. Citizens United was about free speech prevailing over government censorship. The Supreme Court got it right.