“Trump is the key figure,” Mr. Sonenshein said. “He put Cox where he is. The Republican Party is now the Trump Party, and that is more partisan/identity than it is just ideology.”
Mr. Newsom is embracing a platform that would take this state decidedly to the left of Mr. Brown, who was a famous force for moderation in Sacramento. That of course could change should Mr. Newsom find himself sitting behind the governor’s desk, particularly if he faces a recession, as Mr. Brown has warned. As the campaign progressed, Mr. Newsom pulled in his horns on some of his more ambitious promises, saying, for example, that single-payer health care, which was a centerpiece of his campaign, might not happen in his first term.
But for now, he is suggesting a level of ambition — Republicans might describe it as a level of spending — that will mark a break from the past eight years in California.
“These days too many politicians want to tell us what can’t be done,” he said at his victory speech at a San Francisco nightclub on Tuesday night. “But our can-do campaign painted in bold colors and big ideas. Guaranteed health care for all. A Marshall Plan for affordable housing.”
The other critical question for national Democrats and Republicans is what a race like this might mean for voter turnout this fall. In most years, that would not be a big concern, given the state’s propensity to vote for Democrats. But Democrats are looking to capture seven Republican-held congressional seats.
Mr. Newsom had wanted Mr. Cox as his opponent, and ran advertisements intended to boost his prospects. National Democrats had wanted the governor’s race to be a contest between two Democrats, in the calculation that the absence of a Republican on a statewide ballot would mean that Republican voters would have less reason to turn out. Republicans appear to have been shut out in the November race for Senate; early results suggest it will be Senator Dianne Feinstein and a Democratic challenger, Kevin de León, a member of the State Senate.
“If it was two Democrats in the governor’s race and the U.S. Senate race, it would have had a real negative impact on turnout for Republicans in the general election,” said Paul Mitchell, a Sacramento data strategist. “There are few voters — particularly on the Republican side — who are going to be strategically not voting or not voting based on a poll.”