Dianne Feinstein, the oldest serving member of the US Senate who blazed a trail for women in American politics, has died. She was 90.

Feinstein’s death at home in Washington on Thursday night brought down the curtain on a storied career that included gun control advocacy – she spearheaded the first federal assault weapons ban – and documenting the CIA’s torture of foreign terrorism suspects.

The race to succeed her in a safe Democratic seat has attracted high-profile candidates, Adam Schiff, a former House intelligence chair, squaring off against fellow members of Congress Katie Porter and Barbara Lee.

The Democratic governor of California, Gavin Newsom, has promised to install a Black woman in any vacant seat.

Before entering national politics, Feinstein was the first woman to be mayor of San Francisco. She ran for the position twice before in 1978 the assassination of Mayor George Moscone and Harvey Milk, like Feinstein a member of the board of supervisors, saw her step into the top job.

Chris Murphy of Connecticut said in a statement: “For a long time, between 1994 and the tragedy in Newtown in 2012, Dianne was often a lonely but unwavering voice on the issue of gun violence. The modern anti-gun violence movement – now more powerful than the gun lobby – simply would not exist without Dianne’s moral leadership.”

Political activists also praised her legacy. Leah Greenberg, co-executive director of Indivisible, a progressive grassroots movement, said: “Dianne Feinstein was an icon of the Senate. In her decades of trailblazing public service, she broke ground and helped solidify what women could do in American politics again and again.