in U.S. politics, an organization whose purpose is to raise and distribute campaign funds to candidates seeking political office. PACs are formed by corporations, labour unions, trade associations, or other organizations to solicit voluntary campaign contributions from individuals and channel the resulting funds to candidates for elective offices in the federal government, primarily in the House of Representatives and the Senate. PACs rose to prominence after the Federal Election Campaign Act of 1971 set strict limits on the amount of money a particular corporation, union, or private individual could give to a candidate. By soliciting smaller contributions from a much larger number of individuals, PACs circumvent these limitations and manage to provide substantial funds for candidates. By the late 20th century, the vast amounts of money raised by PACs had greatly escalated the cost of running for federal office in the United States.