voters made history on Tuesday in the race for the U.S. Senate, sending two Democrats to a November runoff and denying a Republican a spot on the fall ballot for the first time since the state’s first direct election of senators in 1914.

State Atty. Gen. Kamala Harris won the largest share of the vote and the title of winner in the primary. By the end of the night, Harris led Orange County Rep. Loretta Sanchez by more than 800,000 votes, a margin of 23 percentage points.

Under California’s relatively new top-two primary rules, the two Democratic women will square off on Nov. 8 – a contest that pits Harris’ strength as the party favorite against Sanchez’s potential appeal to Republicans, unaffiliated voters and Latinos.

“Our unity is our strength. Our diversity is our power,” Harris told a boisterous crowd at the Delancey Street Foundation clubhouse in San Francisco on election night. “We understand that we have so many challenges as a country and we are prepared to lead.”

The fact that no Republican could muster enough statewide support to advance to the general election could be a reflection of how an ever-shrinking GOP suffered when its voters were scattered among a large field of relatively unknown candidates.

“If there had been a particular candidate who had been the anointed one, they would have had a better chance at getting that second spot,” said Kimberly Nalder, a political science professor at Cal State Sacramento.

Members of the U.S. Senate were appointed by state legislatures until the early 20th century. Since that time, a Republican has always appeared on the general election ballot in California.

That streak ended on Tuesday night, the third election held under the rules of the top-two primary, in which voters choose a candidate regardless of political party. 

Sanchez, who mingled with supporters gathered at an Anaheim brewpub, celebrated her second-place standing.

“We’ve looked at the numbers. We know we’re going to be there,” she told the crowd.

Republicans continue to lose ground in voter registration to Democrats and have failed to win a single statewide election for a decade.