these, while Republicans won the other two. Among governor's races, Cook correctly predicted that Republicans would win control of the North Carolina governorship, which Democrats had previously controlled. Cook also listed three Democratic-held governorships as "toss-ups": Washington; Montana; and New Hampshire. Democrats ended up holding onto all three. 2014 In the race for control of the US Senate, Cook correctly predicted that Republicans would win control of the Democratic-held Senate seats in Montana, West Virginia, and South Dakota. Cook also listed nine US Senate races as toss-ups; Republicans ended up winning eight of these, while Democrats won only one. Every state Cook listed as at least leaning Republican voted Republican; every state Cook listed as at least leaning Democratic voted Democratic. Among governor's races, Cook correctly predicted that Democrats would flip the Pennsylvania governorship and that Republicans would flip the Arkansas governorship. Democrats won every state Cook rated as at least leaning Democrat; Republicans won every state Cook rated as at least leaning Republican. Cook also rated 13 governor's races as "toss-ups". Democrats ended up winning 3 of these, while Republicans won the other 9; an independent, Bill Walker, won the toss-up governor's race in Alaska. 2016 In the race for control of the US Senate, Cook rated seven Senate seats as "toss-ups", suggesting the two parties had roughly even odds of winning each election. In the end, Democrats won two of these elections and Republicans won five. Cook contributors had expected the toss-up races to break the other way, with Democrats winning most of them. However, Republicans did not win any Senate races that Cook identified as at least leaning toward Democrats; nor did Democrats win any Senate races Cook identified as at least leaning toward Republicans. In the presidential election, Cook incorrectly predicted that Hillary Clinton would win Pennsylvania, Michigan, and Wisconsin; it also rated North Carolina, Florida, Maine's 2nd Congressional District, and Nebraska's 2nd Congressional District as "toss-ups". In the end, Trump won all of these states and districts, though for the most part by narrow margins. All of Cook's other final predictions for the presidential election were correct, though Cook had speculated earlier in the year that Democrats had a chance of success in states they did not end up winning, including Arizona and Texas. Among governor's races, Republicans won every governorship that Cook rated as at least leaning Republican, while Democrats won every governorship Cook