Campaign finance is a controversial issue, pitting concerns about free speech against concerns about corruption and inequality on the part of those who favor existing or further restrictions.
Political money in the United States is often divided into two categories, "hard" money and "soft" money.
"Hard" money is contributed directly to a candidate of a political party. It is regulated by law in both source and amount, and monitored by the Federal Election Commission (maximum $2500).
"Soft" money is contributed to the political party as a whole. Historically, "soft money" referred to contributions made to political parties for purposes of party building and other activities not directly related to the election of specific candidates.