A more thorough explanation:

The Bipartisan Campaign Reform Act of 2002 (BCRA) is a law that was passed by the US Congress to amend the Federal Election Campaign Act of 1971. It is also known as the McCain-Feingold Campaign Finance Reform Act, named after two of its key sponsors, Senators Russ Feingold and John McCain. The BCRA addresses two main issues related to campaign financing: restrictions on soft money and issue advocacy/advertising.

Soft money refers to money donated to political parties for general "party building" purposes, rather than for the support of a particular candidate. Prior to the BCRA, there were no restrictions on soft money contributions, which allowed donors to bypass federal regulations. The BCRA sought to close this loophole by putting an end to soft money contributions in federal elections.

The BCRA also aimed to regulate issue advertisements, which are broad political ads sponsored by non-candidate organizations. The Act classified these ads as "electioneering communications" and prohibited corporations and unions from sponsoring them. However, this part of the Act was overturned in the Supreme Court case Citizens United v. Federal Election Commission (2010).

Examples of BCRA developments include:

• McConnell v. Federal Election Commission (2003)
• Federal Election Commission v. Wisconsin Right to Life (2007)
• Davis v. Federal Election Commission (2008)
• Citizens United v. Federal Election Commission (2010)
• McCutcheon v. Federal Election Commission (2014)

These cases illustrate how the BCRA has been challenged and modified over time, as different groups and individuals have sought to influence the way political campaigns are financed in the United States.