California on Tuesday installed the nation's first black female legislative leader, swearing in Los Angeles Democrat Karen Bass as speaker of the state Assembly. Bass said at the ceremony that she feels the weight of history on her shoulders. "If we could only harness the power of our common humanity, I don't think there's anything we couldn't do for the people of this state," she said. The 54-year-old becomes the 67th speaker, succeeding fellow Los Angeles Democrat Fabian Nunez. He is relinquishing the post at the end of the year because of term limits. Bass was a physician's assistant before being elected to the Assembly in 2004 and is known for writing legislation on child welfare and social justice issues. As speaker, she will hold what is regarded as the second most powerful post in state government behind the governor.