In mid-1949, Nixon, although anxious to advance his political career, was reluctant to run for the Senate unless he was confident of winning the Republican primary.
He considered his party's prospects in the House to be bleak, absent a strong Republican trend, and wrote "I seriously doubt if we can ever work our way back in power.
Actually, in my mind, I do not see any great gain in remaining a member of the House, even from a relatively good District, if it means we would be simply a vocal but ineffective minority."

In late August 1949, Nixon embarked on a putatively nonpolitical speaking tour of Northern California, where he was less well known, to see if his candidacy would be well received if he ran.
With many of his closest advisers urging him to do so, Nixon decided in early October to seek the Senate seat.
He hired a professional campaign manager, Murray Chotiner, who had helped to run successful campaigns for both Governor Warren and Senator Knowland and had played a limited role in Nixon's first congressional race.

Nixon announced his candidacy in a radio broadcast on November 3, painting the race as a choice between a free society and state socialism.
Chotiner's philosophy for the primary campaign was to focus on Nixon and ignore the opposition.
Nixon did not indulge in negative campaigning in the primaries; according to Nixon biographer Irwin Gellman, the internecine warfare in the Democratic Party made it unnecessary.
The Nixon campaign spent most of late 1949 and early 1950 concentrating on building a statewide organization, and on intensive fundraising, which proved successful.

Nixon had built part of his reputation in the House on his role in the Alger Hiss affair.
Hiss's retrial for perjury after a July 1949 hung jury was a cloud over Nixon's campaign; if Hiss was acquitted, Nixon's candidacy would be in serious danger.
On January 21, 1950, the jury found Hiss guilty, and Nixon received hundreds of congratulatory messages, including one from the only living former president, Herbert Hoover.

At the end of January 1950, a subcommittee of the California Republican Assembly, a conservative grassroots group, endorsed former Lieutenant Governor Frederick Houser (who had lost narrowly to Downey in 1944) over Nixon for the Senate candidacy by a 6–3 vote, only to be reversed by the full committee, which endorsed Nixon by 13–12.
Houser eventually decided against running.
Los Angeles County Supervisor Raymond Darby commenced a Senate run, but changed his mind and instead ran for lieutenant governor.
Darby was defeated by incumbent Lieutenant Governor Goodwin Knight in the Republican primary.
Knight had also been considered likely to run for the Senate, but decided to seek re-election instead.
Actor Edward Arnold began a Senate run, but dropped it in late March, citing a lack of time to prepare his campaign.
Nixon was opposed for the Republican nomination only by cross-filing Democrats and by two fringe candidates: Ulysses Grant Bixby Meyer, a consulting psychologist for a dating service, and former judge and law professor Albert Levitt, who opposed "the political theories and activities of national and international Communism, Fascism, and Vaticanism" and was unhappy that the press was paying virtually no attention to his campaign.

On March 20, Nixon cross-filed in the two major party primaries, and two weeks later began to criss-cross the state in his campaign vehicle: a yellow station wagon with "Nixon for U.S. Senator" in big letters on both sides.
According to one contemporary news account, in his "barnstorming tour", Nixon intended to "[talk] up his campaign for the U.S. Senate on street corners and wherever he can collect a crowd."
During his nine-week primary tour, he visited all of California's 58 counties, speaking sometimes six or eight times in a day.
His wife Pat Nixon stood by as her husband spoke, distributing campaign thimbles that urged the election of Nixon and were marked with the slogan "Safeguard the American Home".
She distributed more than 65,000 by the end of the campaign.

A Douglas supporter
In mid-1949, Nixon, although anxious to advance his political career, was reluctant to run for the Senate unless he was confident of winning the Republican primary. He considered his party's prospects in the House to be bleak, absent a strong Republican trend, and wrote "I seriously doubt if we can ever work our way back in power. Actually, in my mind, I do not see any great gain in remaining a member of the House, even from a relatively good District, if it means we would be simply a vocal but ineffective minority."
In late August 1949, Nixon embarked on a putatively nonpolitical speaking tour of Northern California, where he was less well known, to see if his candidacy would be well received if he ran. With many of his closest advisers urging him to do so, Nixon decided in early October to seek the Senate seat. He hired a professional campaign manager, Murray Chotiner, who had helped to run successful campaigns for both Governor Warren and Senator Knowland and had played a limited role in Nixon's first congressional race.
Nixon announced his candidacy in a radio broadcast on November 3, painting the race as a choice between a free society and state socialism. Chotiner's philosophy for the primary campaign was to focus on Nixon and ignore the opposition. Nixon did not indulge in negative campaigning in the primaries; according to Nixon biographer Irwin Gellman, the internecine warfare in the Democratic Party made it unnecessary. The Nixon campaign spent most of late 1949 and early 1950 concentrating on building a statewide organization, and on intensive fundraising, which proved successful.
Nixon had built part of his reputation in the House on his role in the Alger Hiss affair. Hiss's retrial for perjury after a July 1949 hung jury was a cloud over Nixon's campaign; if Hiss was acquitted, Nixon's candidacy would be in serious danger. On January 21, 1950, the jury found Hiss guilty, and Nixon received hundreds of congratulatory messages, including one from the only living former president, Herbert Hoover.
At the end of January 1950, a subcommittee of the California Republican Assembly, a conservative grassroots group, endorsed former Lieutenant Governor Frederick Houser (who had lost narrowly to Downey in 1944) over Nixon for the Senate candidacy by a 6–3 vote, only to be reversed by the full committee, which endorsed Nixon by 13–12. Houser eventually decided against running. Los Angeles County Supervisor Raymond Darby commenced a Senate run, but changed his mind and instead ran for lieutenant governor. Darby was defeated by incumbent Lieutenant Governor Goodwin Knight in the Republican primary. Knight had also been considered likely to run for the Senate, but decided to seek re-election instead. Actor Edward Arnold began a Senate run, but dropped it in late March, citing a lack of time to prepare his campaign. Nixon was opposed for the Republican nomination only by cross-filing Democrats and by two fringe candidates: Ulysses Grant Bixby Meyer, a consulting psychologist for a dating service, and former judge and law professor Albert Levitt, who opposed "the political theories and activities of national and international Communism, Fascism, and Vaticanism" and was unhappy that the press was paying virtually no attention to his campaign.
On March 20, Nixon cross-filed in the two major party primaries, and two weeks later began to criss-cross the state in his campaign vehicle: a yellow station wagon with "Nixon for U.S. Senator" in big letters on both sides. According to one contemporary news account, in his "barnstorming tour", Nixon intended to "[talk] up his campaign for the U.S. Senate on street corners and wherever he can collect a crowd." During his nine-week primary tour, he visited all of California's 58 counties, speaking sometimes six or eight times in a day. His wife Pat Nixon stood by as her husband spoke, distributing campaign thimbles that urged the election of Nixon and were marked with the slogan "Safeguard the American Home". She distributed more than 65,000 by the end of the campaign.
A Douglas supporter 
1950 United States Senate election in California