U.S. Sen. Dianne Feinstein was expected to coast to a fourth full term over a Republican challenger who has never held elective office.

California's senior senator was far better known and better financed than challenger Elizabeth Emken, who lacked political experience and the fundraising skills to mount a credible challenge.

Emken, an autism activist whose only previous campaign experience consists of finishing last among four Republicans in a 2010 congressional primary, beat 23 other little-known candidates in the June primary for a chance to challenge the popular Democratic senator.

Feinstein had gathered more than $8.6 million, despite being one of many Democratic candidates and officeholders victimized in an embezzlement scandal involving a former campaign treasurer. In contrast, Emken had raised roughly $666,000 at the time of the most recent Federal Election Commission filings.

Feinstein, 79, is one of the most popular and well-known politicians in state history. She pushed her case for a fourth full term by stressing her legislative record, especially on the economy and national security, as well as her years of experience in government.

Known as a centrist dealmaker, the former San Francisco mayor has promised to reintroduce the federal ban on assault rifles, leverage her seniority to boost the economy partly through offering tax breaks for innovative businesses and use her position as chairwoman of the Senate Intelligence Committee to halt leaks about sensitive information.

Emken presented herself as a fresh face with a commitment to reform, but she has been unable to overcome the flagging popularity of the California Republican Party and her poor fundraising, which prevented her from mounting a statewide advertising campaign and building a deep network of grassroots supporters.

Emken, who lives in the eastern San Francisco Bay area suburb of Danville, has faulted Feinstein for the rising national debt and California's ailing economy.