At some newspapers, the owner is also the publisher. At others, the owner hires the publisher. The Washington Post was owned by the Meyers-Graham family from 1933 until 2013 and five successive publishers during this period were Eugene Meyer and his direct heirs or in-laws. The Graham family has long been associated with the Democratic party and the editors they hired reflected this association. (The Post made its reputation by breaking the Watergate story in 1972.) Although, in an effort to show balance, they also hired Republican columnists, notably George Will, for their opinion pages.
Their competitor in the Washington market, The Washington Times, was owned by the Unification Church and its leader, Rev. Sun Myung Moon, who favored conservative causes and candidates, and who hired publishers who shared this preference. This was primarily in evidence on their editorial page, which was staunchly pro-Republican, although their coverage of local news was surprisingly non-partisan.
Some owners and publishers use their newspaper as a bully-pulpit for their partisan political agendas (this is known as "advocacy journalism"). Other owners, committed to objective news coverage, take a hands-off approach and trust their publishers/editors to pursue news coverage with no obvious political bias. Both are valid approaches to journalism. The mark of a good newspaper is to see what they do with news and information that conflicts with its apparent agenda; the best will publish the facts wherever they lead.