The 2018 Senate map was much more favorable to Republicans, who needed to defend only nine seats, compared with Democrats’ 26. Ten Democrats sought reelection in states President Trump won. Republicans were favored to control the chamber and possibly grow their 51-to-49 majority.
To retake the chamber, Democrats would have had to defend against formidable Republican challenges, win open seats in Arizona and Tennessee, oust a vulnerable Republican in Nevada and flip traditionally red Texas.
Congress this week is poised to pursue two diverging strategies for ending the partial government shutdown, but it is far from clear how Republicans and Democrats will reconcile their differences and reopen the government.