Hillary Clinton named Virginia Sen. Tim Kaine as her running mate for the Democratic presidential ticket, a widely anticipated choice that may say more about how she wants to govern than how she plans to win in November.

Clinton made the announcement Friday in a text message to supporters. "I'm thrilled to tell you this first: I've chosen Tim Kaine as my running mate. Welcome him to our team," it said. In a message on Twitter, Clinton said Kaine has dedicated his life to fighting for others, and described him as "a relentless optimist." The pair were to appear Saturday in Miami.

Clinton called Kaine at 7:32 p.m. Washington time to make it official, according to a campaign official, who asked for anonymity. Clinton then spoke with President Barack Obama.