Pundits largely see Democrats as favorites to win back control of the House but as underdogs in winning back the Senate. To take a Senate majority, the party has to net two seats in November.
While flipping the Senate appears daunting for Democrats, the party does have a path to do so. It would require winning eight of the 10 battleground races considered most competitive. For example, if only one incumbent Democrat loses, the party would have to defend all its other seats and flip three GOP-held seats to take a majority.
If Republicans knock out two Democratic senators, it all but assures them they will keep their majority, unless Democrats can pull off a nearly clean sweep of accessible Republican seats.
Earlier this week, Senate Majority Leader Mitch McConnell described the 10 races listed above — excluding Texas — "too close to call and every one of them like a knife fight in an alley, just a brawl." He separately called the Texas race between Republican Sen. Ted Cruz and Democrat Beto O'Rourke "competitive."
To put a figure on it, models made by widely followed data guru Nate Silver's FiveThirtyEight give Democrats about a 1-in-3 chance of taking the Senate. The average projected outcome leaves the Senate right about where it started, with the GOP holding a 51-49 majority.
In assessing the potential outcomes, Silver writes that "just as Republicans are far from doomed in the House, they are far from safe in the Senate." Still, the site's models see a Democratic House and a Republican Senate as the most likely scenario after November's elections.
A number of factors, including Trump's approval rating, the congressional generic ballot and the money that flows into each of the contests, could change the likelihood of the Senate flipping between now and November. In addition, a handful of races for seats not outlined here could become more competitive.