"Concerns over financing federal elections have become a seemingly perennial aspect of our political system, long centered on the enduring issues of high campaign costs and reliance on interest groups for needed campaign funds. Rising election costs had long fostered a sense in some quarters that spending was out of control, with too much time spent raising funds and elections 'bought and sold.' Debate had also focused on the role of interest groups in campaign funding, especially through political action committees (PACs). Differences in perceptions of the campaign finance system were compounded by the major parties' different approaches. Democrats tended to favor more regulation, with spending limits and public funding or benefits a part of past proposals. Republicans generally opposed such limits and public funding."
CRS Issue Brief for Congress, IB87020
U.S. Department of State: http://www.state.gov/