U.S. Senator Cory Booker speaks at a county Democratic fundraiser in Marshalltown, Iowa, on Sept. 21, 2019. He said then he was on the verge of leaving the presidential race unless he could raise an additional $1.7 million by the end of the month. Booker finally did suspend his campaign on Jan. 13, 2020, just weeks before Iowa voters are to caucus in the country’s first primary contest.