Wow, I just found out about another thing James Buckley had a hand in. I always thought he was the more influential of the two brothers.

Buckley v. Valeo:

Buckley v. Valeo, 424 U.S. 1 (1976), was a case in which the Supreme Court of the United States upheld a federal law which set limits on campaign contributions, but ruled that spending money to influence elections is a form of constitutionally protected free speech, and struck down portions of the law. The court also ruled candidates can give unlimited amounts of money to their own campaigns.

I tripped across this while looking up an article about John Heinz, former moderate Republican from PA.