As Biden Decides on Running Mate, Kamala Harris Stresses Law-Enforcement Roles

As a presidential candidate, Sen. Kamala Harris repeatedly tried to explain her record on criminal justice and told voters stories about her family’s history of activism in the civil-rights movement.

But Ms. Harris was met with skepticism, especially from progressives who wrote her off because of her career in law enforcement, which helped to lead the California senator to drop out of the race much earlier than expected.

Now Ms. Harris is viewed by party leaders as a top potential choice as former Vice President Joe Biden’s running mate. She...