How did Citizens United v. Federal Election Commission change the Bipartisan Campaign Reform Act?

In the 2010 case Citizens United v. Federal Election Commission, the U.S. Supreme Court fundamentally altered the Bipartisan Campaign Reform Act (BCRA) of 2002 by invalidating key restrictions on political spending.12

Specifically, the Court ruled that Section 203 of the BCRA—which prohibited corporations and labour unions from using their general treasury funds to broadcast "electioneering communications" (political advertisements) within 30 days of a primary election or 60 days of a general election—was an unconstitutional infringement on the First Amendment right to freedom of speech.12

By striking down these provisions, the Court effectively overturned its own previous ruling in McConnell v. Federal Election Commission (2003), which had upheld the BCRA's limitations on such advocacy. This decision removed the federal ban on independent political expenditures by corporations and unions, allowing them to spend unlimited amounts of money on advertisements that support or oppose political candidates, provided those expenditures are not coordinated directly with a candidate's campaign.12