Senator Tim Kaine told the Richmond Times-Dispatch that he would not run for president or vice-president again, and will focus on reelection to the Senate in 2018. He cites John Warner, the long-serving Republican senator of his home state of Virginia, as the model he hopes to emulate.
This means that the Democratic field for 2020 will be truly open – think the Republicans in 2008 or 2012 with no presidential or vice presidential nominee running for the spot.