Sanders opened his speech with a nod to his near tie with Hillary Clinton in the Kentucky primary, which still hadn't been called. He categorized the nature of the race in Kentucky as the result of the state party's closed primary system and railed against those who have called for him to drop out of the Democratic presidential race, saying they don't want late primary states like California to weigh in.
"In a closed primary, something I am not all that enthusiastic about where independents are not allowed to vote, where Secretary Clinton defeated Barack Obama by 250,000 votes in 2008, it appears tonight that we are gonna end up with about half of the delegates from Kentucky," Sanders said.
"I want to thank you all for coming out because this is in a sense is the beginning of the final push to win California," he added.
Sanders said he recognized that it would be a "steep climb" to arrive at the Democratic National Convention in Philadelphia with a majority of pledged delegates, though.
"Now some people say that we've got a steep hill to climb to do that. And that is absolutely true," he said. "But you know what, together, we have been climbing that steep hill from day one in this campaign. And we are going to continue to fight for every last vote until June 14th, and then we're going to take our fight into the convention."
The Vermont senator also took a break from his typical stump speech to rail against the Democratic National Committee, which he and his supporters have often butted heads with, most recently at the Nevada Democratic Convention last weekend. When he brought up the DNC to boos from the crowd, Sanders called upon Democratic leaders to be more inclusive of his progressive supporters.
"The Democratic party is going to have to make a very, very profound and important decision," Sanders said. "It can do the right thing and open its doors and welcome into the party. So I say to the leadership of the Democratic Party, open the doors, let the people in."
Sanders' wife, Jane, at one point interrupted the speech to tell her husband about his victory in Oregon, which he announced to cheers from the crowd.
"I'm beginning to like the West Coast," he said with a smile.