Party leaders are big fans of conventions because:

a. the convention system gives them opportunity to take care of the other party business besides nominating candidates.

b. they can rally the party faithful with platforms for debate and decisions.

c. candidates can judge whether they are in line with the rest of the party.

d. the party can "fine-tune" its organization, finding where it is weak and working to correct the weakness.

e. sponsors must swear that they know the candidate personally and consider him qualified for the office he is seeking.