The most important political event this week won't be Obama's speech on health care.

WASHINGTON -- President Obama's health care speech on Wednesday will be only the second most consequential political moment of the week.

Judged by the standard of an event's potential long-term impact on our public life, the most important will be the argument before the Supreme Court (on the same day, as it happens) about a case that, if decided wrongly, could surrender control of our democracy to corporate interests.

This sounds melodramatic. It's not. The court is considering eviscerating laws that have been on the books since, in one case, 1907 and in the other, 1947 banning direct contributions and spending by corporations in federal election campaigns. Doing so would obliterate precedents that go back two and three decades.

The full impact of what the court could do in Citizens United v. Federal Election Commission has only begun to receive the attention it deserves. Even the word "radical" does not capture the extent to which the justices could turn our political system upside down. Will it use a case originally brought on a narrow issue to bring our politics back to the corruption of the Gilded Age?

Citizens United, a conservative group, brought suit arguing that it should be exempt from the restrictions of the 2002 McCain-Feingold campaign finance law for a movie it made that was sharply critical of Hillary Clinton. The organization said it should not have to disclose who financed the film.