As the court reasoned in 1976, the message implicit in a campaign contribution--I support Candidate X--has little to do with the size of the contribution.
If you support a candidate you don't have to contribute to their campaign. 
mnli hypothesis: If you support a candidate you don't have to contribute to their campaign.  premise: As the court reasoned in 1976, the message implicit in a campaign contribution--I support Candidate X--has little to do with the size of the contribution.