Answer:
The answer to the question: What is the primary difference between "hard" and "soft" money, would be: first, that hard money is purposefully money given to support a candidate from a party, while soft money is given to parties for the purpose of building the party and their purposes. The second difference is that hard money is now heavily regulated by the Federal Elections Comission.
Explanation:
The issue of how campaigns, and parties, were able acquire the money to both launch their candidates, and party-related activities outside of campaigning time, became really important after it became evident that the regulations placed on donations from individuals, companies, or any sector, for that matter, through the passage of rules in 1978, were being violated. As such, parties were discovered to be using "soft" money as a means to also finance candidates and the "party activities" which were supposed to be financed by "soft" money but were not supposed to tell the electorate who to vote for, was doing exactly the opposite. As of today, and after 1988, "hard" money and even soft money were regulated, but there is a much stricter control on "hard" money.