The Federal Election Campaign Act of 1971 (FECA, Pub.L. 92–225, 86 Stat. 3, enacted February 7, 1972, 52 U.S.C. § 30101 et seq.) is the primary United States federal law regulating political campaign spending and fundraising. The law originally focused on increased disclosure of contributions for federal campaigns. The S. 382 legislation was passed by the 92nd U.S. Congressional session and signed by the 37th President of the United States Richard Nixon on February 7, 1972.
In 1974, the Act was amended to place legal limits on the campaign contributions and expenditures. The 1974 amendments also created the Federal Election Commission (FEC).
The Act was amended again in 1976, in response to the provisions ruled unconstitutional by Buckley v. Valeo, including the structure of the FEC and the limits on campaign expenditures, and again in 1979 to allow parties to spend unlimited amounts of hard money on activities like increasing voter turnout and registration. In 1979, the FEC ruled that political parties could spend unregulated or "soft" money for non-federal administrative and party building activities. Later, this money was used for candidate-related issue ads, which led to a substantial increase in soft money contributions and expenditures in elections. This in turn led to passage of the Bipartisan Campaign Reform Act of 2002 ("BCRA"), effective on January 1, 2003, banning soft money expenditure by parties. Some of the legal limits on giving of "hard money" were also changed by BCRA.
In addition to limiting the size of contributions to candidates and political parties, FECA also requires campaigns and political committees to report the names, addresses, and occupations of donors of more than $200.
The FECA contains an express preemption clause. The FECA expressly preempts state and federal law with respect to federal elections.
This summary is from Wikipedia.