A 2010 Supreme Court ruling that overturned aspects of the McCain-Feingold Act on the use of corporate and union money in elections.

In a controversial 5-4 decision, the Supreme Court ruled that corporations should be viewed the same way as individuals in terms of their First Amendment right to free speech.

Using that rationale, it overturned a ban on corporate and union spending on advertisements that mention a candidate's name within 60 or 30 days of an election (depending on whether it is a general or primary election).

Now, unions and corporations will be able to directly advertise right up until election day, as long as they haven't co-ordinated their advertisements with a candidate's campaign.

The ruling maintained the McCain-Feingold Act's ban on corporations and unions directly donating to candidates and political parties, as well as the requirement for ads to disclose their funding sources.