quote at Robert F. Kennedy's grave site at Arlington National Cemetery

Forty years ago, Democratic presidential candidate Sen. Robert F. Kennedy of New York was assassinated within minutes of declaring victory in the California primary.

Nursing a grudge because of the candidate's support of Israel, a 24-year-old Palestinian nationalist named Sirhan Sirhan shot the Democratic front-runner as he passed through the kitchen of the Ambassador Hotel in Los Angeles.

What should have been a night of triumph turned into a familiar night of horror for the Kennedy family and the nation. Less than five years earlier, President John F. Kennedy had been felled by an assassin's bullet.

As shocking as the specter of another fallen Kennedy was, the senator's murder came only two months after the Rev. Martin Luther King Jr. was assassinated in Memphis. It felt inevitable in a way. It had been a bad year for charismatic leaders and the dreams they fostered.

Forty years later, the nation looks back on the murders with fascination and dread. Somehow it made it through some of the darkest days of its history, with democracy intact.

Many Americans miss Bobby Kennedy, but they prove they were truly inspired by him when they stand up against injustice the way he did. It is up to those who champion his memory to stir tiny ripples of hope.