Federal law has regulated money in elections for more than a century. Concerns about limiting the potential for corruption and informing voters have been at the heart of that law and related regulations and judicial decisions . Restrictions on private money in campaigns, particularly large contributions, have been a common theme throughout the history of federal campaign finance law. The roles of corporations, unions, interest groups, and private funding from individuals have attracted consistent regulatory attention. Congress has also required that certain information about campaigns' financial transactions be made public. Collectively, three principles embodied in this regulatory tradition—limits on sources of funds, limits on contributions, and disclosure of information about these funds—constitute ongoing themes in federal campaign finance policy. Throughout most of the 20 th century, campaign finance policy was marked by broad legislation enacted sporadically. Major legislative action on campaign finance issues remains rare. Since the 1990s, however, momentum on federal campaign finance policy, including regulatory and judicial action, has arguably increased. Congress last enacted major campaign finance legislation in 2002. The Bipartisan Campaign Reform Act (BCRA) largely banned unregulated soft money in federal elections and restricted funding sources for pre-election broadcast advertising known as electioneering communications . As BCRA was implemented, regulatory developments at the Federal Election Commission (FEC), and some court cases, stirred controversy and renewed popular and congressional attention to campaign finance issues. Since BCRA, Congress has also continued to explore legislative options and has made comparatively minor amendments to the nation's campaign finance law. The most notable recent statutory changes occurred in 2014, when Congress eliminated public financing for presidential nominating conventions and increased limits for some contributions to political parties. Some of the most recent notable campaign finance developments beyond Congress have occurred at the Supreme Court. The 2010 Citizens United ruling spurred substantial legislative action during the 111 th Congress and continued interest during subsequent Congresses. The ruling was, however, only the latest—albeit perhaps the most monumental—shift in federal campaign finance policy to occur in recent years. In another 2010 decision, SpeechNow.org v. Federal Election Commission , the U.S. Court of Appeals for the District of Columbia held that contributions to political action committees (PACs) that make only independent expenditures cannot be limited—a development that led to formation of "super PACs." This report is intended to provide an accessible overview of major policy issues facing Congress. Citations to other CRS products, which provide additional information, appear where relevant. The report discusses selected litigation to demonstrate how those events have changed the campaign finance landscape and affected the policy issues that may confront Congress, but it is not a constitutional or legal analysis. As in the past, this version of the report contains both additions of new material and deletions of old material compared with previous versions. This update emphasizes those topics that appear to be most relevant for Congress, while also providing historical background that is broadly applicable. This report will be updated occasionally as events warrant. Dozens or hundreds of campaign finance bills have been introduced in each Congress since the 1970s. Nonetheless, major changes in campaign finance law have been rare. A generation passed between the Federal Election Campaign Act (FECA) and BCRA, the two most prominent campaign finance statutes of the past 50 years. Federal courts and the FEC played active roles in interpreting and implementing both statutes and others. Over time and in all facets of the policy process, anti-corruption themes have been consistently evident. Specifically, federal campaign finance law seeks to limit corruption or apparent corruption in the lawmaking process that might result from monetary contributions. Campaign finance law also seeks to inform voters about sources and amounts of contributions. In general, Congress has attempted to limit potential corruption and increase voter information through two major policy approaches limiting sources and amounts of financial contributions, and requiring disclosure about contributions and expenditures. Another hallmark of the nation's campaign finance policy concerns spending restrictions. Congress has occasionally placed restrictions on the amount candidates can spend, as it did initially through FECA. Today, candidates and political committees can generally spend unlimited amounts on their campaigns, as long as those funds are not coordinated with other parties or candidates. Modern campaign finance law was largely shaped in the 1970s, particularly through FECA. First enacted in 1971 and substantially amended in 1974, 1976, and 1979, FECA remains the foundation of the nation's campaign finance law. As originally enacted, FECA subsumed previous campaign finance statutes, such as the 1925 Corrupt Practices Act, which, by the 1970s, were largely regarded as ineffective, antiquated, or both. The 1971 FECA principally mandated reporting requirements similar to those in place today, such as quarterly disclosure of a political committee's receipts and expenditures. Subsequent amendments to FECA played a major role in shaping campaign finance policy as it is understood today. In brief Among other requirements, the 1974 amendments, enacted in response to the Watergate scandal, placed contribution and spending limits on campaigns. The 1974 amendments also established the FEC. After the 1974 amendments were enacted, the first in a series of prominent legal challenges (most of which are beyond the scope of this report) came before the Supreme Court of the United States. In its landmark Buckley v . Valeo (1976) ruling, the Court declared mandatory spending limits unconstitutional (except for publicly financed presidential candidates) and invalidated the original appointment structure for the FEC. Congress responded to Buckley through the 1976 FECA amendments, which reconstituted the FEC, established new contribution limits, and addressed various PAC and presidential public financing issues. The 1979 amendments simplified reporting requirements for some political committees and individuals. To summarize, the 1970s were devoted primarily to establishing and testing limits on contributions and expenditures, creating a disclosure regime, and constructing the FEC to administer the nation's campaign finance laws. Despite minor amendments, FECA remained essentially uninterrupted for the next 20 years. Although there were relatively narrow legislative changes to FECA and other statutes, such as the 1986 repeal of tax credits for political contributions, much of the debate during the 1980s and early 1990s focused on the role of interest groups, especially PACs. By the 1990s, attention began to shift to perceived loopholes in FECA. Two issues—soft money and issue advocacy (issue advertising)—were especially prominent. Soft money is a term of art referring to funds generally perceived to influence elections but not regulated by campaign finance law. At the federal level before BCRA, soft money came principally in the form of large contributions from otherwise prohibited sources, and went to party committees for "party-building" activities that indirectly supported elections. Similarly, issue advocacy traditionally fell outside FECA regulation because these advertisements praised or criticized a federal candidate—often by urging voters to contact the candidate—but did not explicitly call for election or defeat of the candidate (which would be express advocacy ). In response to these and other concerns, BCRA specified several reforms. Among other provisions, the act banned national parties, federal candidates, and officeholders from raising soft money in federal elections; increased most contribution limits; and placed additional restrictions on pre-election issue advocacy. Specifically, the act's electioneering communications provision prohibited corporations and unions from using their treasury funds to air broadcast ads referring to clearly identified federal candidates within 60 days of a general election or 30 days of a primary election or caucus. After Congress enacted BCRA, momentum on federal campaign finance policy issues arguably shifted to the FEC and the courts. Implementing and interpreting BCRA were especially prominent issues. Noteworthy post-BCRA events include the following: The Supreme Court upheld most of BCRA's provisions in a 2003 facial challenge ( McConnell v. Federal Election Commission ). Over time, the Court held aspects of BCRA unconstitutional as applied to specific circumstances. These included a 2008 ruling related to additional fundraising permitted for congressional candidates facing self-financed opponents (the "Millionaire's Amendment," Davis v. Federal Election Commission ) and a 2007 ruling on the electioneering communication provision's restrictions on advertising by a 501(c)(4) advocacy organization ( Wisconsin Right to Life v. Federal Election Commission ). Since 2002, the FEC has undertaken several rulemakings related to BCRA and other topics. Complicated subject matter, protracted debate among commissioners, and litigation have made some rulemakings lengthy and controversial. Congress enacted some additional amendments to campaign finance law since BCRA. The 2007 Honest Leadership and Open Government Act (HLOGA) placed new disclosure requirements on lobbyists' campaign contributions (certain bundled contributions) and restricted campaign travel aboard private aircraft. In 2014, as discussed below, Congress raised some limits for contributions to political parties. The following discussion highlights those topics that appear to be enduring and significant in the current policy environment. The discussion begins with changes directly affected by Citizens United because those developments most fundamentally altered the campaign finance landscape. In January 2010, the Supreme Court issued a 5-4 decision in Citizens United v. Federal Election Commission . In brief, the opinion invalidated FECA's prohibitions on corporate and union treasury funding of independent expenditures and electioneering communications. As a consequence of Citizens United , corporations and unions are free to use their treasury funds to air political advertisements and make related purchases explicitly calling for election or defeat of federal or state candidates ( independent expenditures ) or advertisements that refer to those candidates during pre-election periods, but do not necessarily explicitly call for their election or defeat ( electioneering communications ). Previously, such advertising would generally have had to be financed through voluntary contributions raised by PACs affiliated with unions or corporations. DISCLOSE Act Consideration Following Citizens United . Since Citizens United , the House and Senate have considered various legislation designed to increase public availability of information ( disclosure ) about corporate and union spending. Particularly in the immediate aftermath of the decision, during the 111 th Congress, most congressional attention responding to the ruling focused on the DISCLOSE Act ( H.R. 5175 ; S. 3295 ; S. 3628 ). The House of Representatives passed H.R.