Soft money goes to the political parties, not the candidates. By strengthening parties, soft money helps American democracy in three ways. First, political parties unite individuals and groups behind a general program for the whole society. If we ban soft money, special interests will play a larger role in our elections. Second, political parties are a buffer against corruption.
Parties solicit soft money and spend it supporting their candidates.
The winners are beholden to their party and not to individual donors. Soft money actually is less of a danger than money given directly to a candidate's campaign. Third, soft money can increase electoral competition. Soft money can help challengers compete with incumbents. Parties make sure soft money ends up where it's needed most.