Americans are electing a president today, but just as importantly, they're deciding which party controls the U.S. Senate. Currently, Republicans hold a 53-47 advantage, so Democrats need to gain a net of four seats to take the majority, or a gain of three seats if they win the White House (since the Vice President breaks all ties in the Senate.) This year's Senate map is more favorable to Democrats, with Republicans defending vulnerable incumbents in Arizona, Colorado, Montana, Iowa, North Carolina, Maine, and both seats in Georgia. Democrats have only two vulnerable seats, in Alabama and Michigan.
Democrats think they have a good shot to win control of the Senate this year. The key to which party has the majority may lie in a couple of southern states. "There's a chance Republicans can hold the seats that they've got and also pick up a few--Alabama is a good example of that," says Brandon Rottinghaus, political science professor at the University of Houston. "They're also hoping to hold in Georgia, where it's been really tight...I think as goes Georgia in terms of where the electorate goes, we'll likely see the rest of the Senate races follow along."
As for the race in Texas between Sen. John Cornyn and Democratic challenger M.J. Hegar, that appears to be an uphill battle for Dems. "M.J. Hegar's problem has been that she's not as well known as John Cornyn and/or as other challengers...like for instance, Beto O'Rourke, who ran in 2018," says Rottinghaus.
Whomever comes out on top in the Senate after Election Day, it will be just as important as the winner of the White House. "The biggest factor in the Trump administration has been the appointment of federal judges," says Rottinghaus. "He has appointed a third of the federal judiciary and three members of the U.S. Supreme Court."
"Democrats would like to change that, but the only way they can do that is with control of the U.S. Senate."