Bernie Sanders on 2020 presidential run: 'We're going to win'

US Senator Bernie Sanders says he will run again for president in 2020, making a second attempt to win the Democratic Party's nomination.

When asked on CBS This Morning what the difference was this time, he said: "We're going to win."

The 77-year-old Vermont senator ran for the party's nomination in 2016, but lost to Hillary Clinton.

Which Democrats are running in 2020?