Early Fund-Raising Divides the Democratic Field Into Haves and Have-Nots. Presidential Election of 2020, Campaign Finance, United States Politics and Government, Political Advertising, Online Advertising, Warren, Elizabeth, Buttigieg, Pete (1982- ), Delaney, John (1963- ), Gillibrand, Kirsten E, Harris, Kamala D, O'Rourke, Beto, Sanders, Bernard