The win helps him gain ground as he tries to keep Clinton from clinching the nomination.
Sanders is speaking to supporters in Louisville, Ky.
A new poll puts Clinton ahead by 10 points in California.
“Well, that is one way to phrase it,” Sanders said approvingly.
Sanders will speak in Washington, two days before Indiana's primary.
"The problem is that the Democrats are losing elections,” he said.
"You need somebody that has the moral judgment beforehand, not when it’s safe."
Sanders sought to tamp down speculation that he’s just seeking to influence the party’s platform
"I look forward to issue-oriented campaigns in the 14 contests to come."
The win will give Clinton the majority of the state’s 55 pledged delegates.