“I would not be here as a presidential candidate were it not for some of the battles he fought as a senator. He battled for voting rights and civil rights when I was a child. I stand on his shoulders.” Those were Senator Barack Obama’s words Tuesday as he responded to news reports that Senator Ted Kennedy had been diagnosed with a malignant brain tumor.

In his 45 years as the Senate’s fighting liberal, Kennedy has been a tenacious champion of civil rights, health care, labor rights, education and a sane foreign policy. As historian Ronald Steel observed the other day, he was a Senator “who showed how government could be made to serve the people.”

Kennedy once said that ” the best vote I’ve cast in my 44 years in the US Senate” was the one he cast against President Bush’s 2002 Iraq war authorization Resolution.

As a result of his opposition to Iraq, and through his support of the most vulnerable and the voiceless, his support of causes lost and found, Kennedy has set the standard for leadership and shown through his credo of perseverance what we must do to rebuild this country and reengage the world.

At the Nation, our hearts sank when we heard the news. But if there is one thing we know about Senator Kennedy, it’s that he’s a fighter.