Presidential campaigns in the United States are incredibly expensive endeavors, financed through a complex web of sources subject to legal regulations designed to maintain fairness and transparency. The funding landscape has evolved significantly over time, particularly in the wake of landmark Supreme Court decisions. Individual contributions are a foundational element. Federal law limits how much individuals can donate directly to a campaign committee. These limits are adjusted periodically to account for inflation. Small-dollar donations, often solicited online, can contribute significantly, particularly for grassroots campaigns. Political Action Committees (PACs) are another key source. Traditional PACs can contribute directly to candidate campaigns, although subject to contribution limits. Super PACs, officially known as Independent Expenditure-Only Committees, are a more recent development. Established after the Citizens United Supreme Court decision, they can raise unlimited sums of money from corporations, unions, and individuals. However, they are legally prohibited from coordinating directly with candidate campaigns. They can only engage in independent spending to advocate for or against a candidate. Party committees, such as the Democratic National Committee (DNC) and the Republican National Committee (RNC), also provide significant financial support. They can contribute directly to candidate campaigns within limits and also spend independently on activities like voter outreach and advertising. Candidate personal wealth is another potential funding source. Candidates are legally permitted to spend unlimited amounts of their own money on their campaigns, a right often invoked by wealthy individuals seeking office. This can create an uneven playing field, potentially disadvantaging candidates without significant personal resources. Public financing is an option available to presidential candidates. If a candidate agrees to abide by spending limits, they can receive matching funds from the government for the primary election. However, this system has become less popular, as the spending limits associated with it are often viewed as too restrictive in the context of modern campaign costs. Most major party nominees opt out of public financing for the general election, preferring to raise and spend unlimited amounts. Campaign finance regulations are enforced by the Federal Election Commission (FEC). The FEC oversees campaign finance laws, ensuring compliance with disclosure requirements and investigating potential violations. However, the FEC has faced criticism for its partisan gridlock, which can hinder its ability to effectively enforce the law. The immense sums of money involved in presidential campaigns raise concerns about potential corruption and undue influence. Critics argue that large contributions from wealthy donors and corporations can distort the political process and give special interests an outsized voice. Supporters of current campaign finance regulations emphasize the importance of free speech and argue that restrictions on campaign spending can stifle political expression. Debates about campaign finance reform continue to be central to discussions about the integrity and fairness of American elections.