California Teacher Credentialing Examination (CSET) Practice Test

Hiram Johnson was known as a prominent Progressive governor of California who took significant steps to diminish the influence of the Southern Pacific Railroad, which had a strong grip on state politics and governance. His tenure in the early 20th century was characterized by reforms aimed at increasing government accountability and reducing corruption that was heavily tied to the railroad's political machinations.

Johnson implemented various reforms, including the establishment of the public utilities commission and extensive campaign finance reforms, which helped to regulate the powerful interests of the Southern Pacific Railroad. By prioritizing the needs and welfare of the citizens over those of powerful corporations, he exemplified the Progressive movement's dedication to promoting social justice and government reform.

The other figures mentioned in the options, while influential in their own right, did not focus on breaking the influence of the Southern Pacific Railroad in the manner that Hiram Johnson did during his governorship.