I propose the following amendment to the United States Constitution:
"Section 1. No citizen or organization may contribute money more than one percent of the President's annual salary to a single political campaign.
Section 2. The Congress shall have power to enforce this article by appropriate legislation."
The President's annual salary is currently $400,000, so this would limit campaign contributions to $4,000. The reason for using the President's salary as a benchmark is to account for inflation.