First-term Senator Chris Van Hollen of Maryland chaired the DSCC for the 2017–2018 election cycle. Before the 2018 elections, Democrats held 49 seats in the U.S. Senate while Republicans held 51. The unusually imbalanced 2018 Senate map, created by successful 2006 and 2012 elections, resulted in a large number of vulnerable Democrats. Joe Donnelly of Indiana, Claire McCaskill of Missouri, Joe Manchin of West Virginia, Heidi Heitkamp of North Dakota, Jon Tester of Montana and Bill Nelson of Florida were seen as the most vulnerable. On November 6, incumbent Democrats in four states were unseated; Donnelly was unseated by State Rep. Mike Braun, McCaskill was defeated by Missouri Attorney General Josh Hawley, Heitkamp was defeated by Kevin Cramer, representative for North Dakota's at-large congressional district, and Nelson was defeated by then Governor Rick Scott. The DSCC considered open seats in Arizona and Tennessee, Dean Heller's seat in Nevada and potentially Ted Cruz's seat in Texas and Cindy Hyde-Smith's seat in Mississippi as possible targets. Of those potentially vulnerable seats, Democrats picked up the open seat in Arizona vacated by Jeff Flake, with Rep. Kyrsten Sinema defeated Rep. Martha McSally, as well as the seat in Nevada held by Dean Heller, being defeated by Rep. Jacky Rosen, leaving the Senate's balance at 53–47, with Republicans in control. 2019-2021 election cycle First-term Senator Catherine Cortez Masto of Nevada chaired the DSCC for the 2019-2020 election cycle, the first Latina to do so. Before the 2020 elections, Democrats held 47 seats, while Republicans held 53. In order to have gained a majority, Democrats would have needed to win at least 4 seats, or 3 seats (and gain the presidency) in the Senate. If they won the presidency, Democrats would have been able to gain a majority with 48 seats (assuming the two Independents continued to caucus with them) because, in event of a tie vote, the Vice President becomes the tie-breaker. Democrats needed to defend 12 seats this cycle, with only 2 in states Donald Trump won, Alabama and Michigan. In Alabama, Senator Doug Jones had only managed to win due to an extremely flawed candidate in (Roy Moore), and was expected to lose due to the strong Republican lean there, which he did. In Michigan, Senator Gary Peters faced a very strong Republican candidate, businessman John James, but was nevertheless expected to win. Republicans, on the other hand, needed to defend 21