In 1978, Clark received some 377,960 votes, 5.46% of the popular vote, in a race for Governor of California. Although a member of the Libertarian Party, he appeared on the California ballot as an independent candidate. Another factor leading to the unprecedented 5.46% vote total for Clark was his libertarian campaign occurring the same year as the successful Proposition 13 which limited property taxes, and the unsuccessful anti-gay Briggs Initiative. Clark and the California Libertarian Party campaigned in support for Proposition 13 and in opposition to Proposition 6 both of which turned out people to the polls who might be more inclined to favor a libertarian candidate. Clark lost the race to Jerry Brown, who was re-elected with 56% of the vote. Republican nominee Evelle J. Younger had 36.5% of the vote.
In 1979 Clark won the Libertarian Party presidential nomination at the party's convention in Los Angeles, California. He published a book on his programs, A New Beginning, with an introduction by Eugene McCarthy. During the campaign, Clark positioned himself as a peace candidate and emphasized both large budget and tax cuts, as well as outreach to liberals and progressives unhappy with the resumption of Selective Service registration and the arms race with the Soviet Union. Clark was endorsed by the Peoria Journal Star of Peoria, Illinois. When asked in a television interview to summarize libertarianism, Clark used the phrase "low-tax liberalism," causing some consternation among traditional libertarian theorists, most notably Murray Rothbard. Clark's running to the center marked the start of a split within the Libertarian Party between a moderate faction led by Ed Crane and a radical faction led by Rothbard that eventually came to a head in 1983, with the moderate faction walking out of the party convention after the nomination for the 1984 presidential race went to David Bergland. Ed Clark's running mate in 1980 was David H. Koch of Koch Industries, who pledged part of his personal fortune to the campaign for the vice-presidential nomination, enabling the Clark/Koch ticket to largely self-fund and run national television advertising. Clark received 921,128 votes ; the highest number and percentage of popular votes a Libertarian Party candidate had ever received in a presidential race up to that point. His strongest support was in Alaska, where he came in third place with 11.66% of the vote, finishing ahead of independent candidate John Anderson and receiving almost half as many votes as Jimmy Carter. Clark's record for most votes won by a Libertarian presidential candidate stood for 32 years until it was broken by Gary Johnson in 2012. His Libertarian vote percentage of 1.06% still ranks 2nd behind Johnson's 3.24% showing in 2016.
