New York City Mayor Bill de Blasio has formally announced his 2020 presidential campaign. The bid was launched with a YouTube video announcing his campaign for president, and will be followed by an appearance on Good Morning America Thursday morning. De Blasio joins a field of nearly two-dozen candidates vying to be the Democratic nominee in 2020. His first campaign stops are expected to be in Iowa and South Carolina, two early-voting states critical to the nominating process. The central theme of de Blasio’s campaign will be “working people first.”