Dem
51
Ties
1
GOP
48
Many pundits are comparing the 2016 midterms to Donald Trump's first midterm, in 2018. Jessica Taylor at The Cook Political Report thinks that is the wrong benchmark. She thinks it should be 2006 (note: paywall).
In that year, Democrats were also facing a bad map, George W. Bush was engaged in an unpopular war in the Middle East, and the economy was in poor shape. Toward the end, Democrats began smelling victory in red states, something not on the table at the start of the cycle. In the end, Democrats flipped Montana, Missouri, Ohio, Virginia, Pennsylvania and Rhode Island, beating incumbent Republicans in all six of them. This time, four of the most contentious races are open seats, where a Republican retired (voluntarily or otherwise). They are Iowa, Montana, North Carolina, and Texas. Winning an open-seat race is always easier than beating a well-known, entrenched incumbent.
The main lesson from 2006 is that when the president is unpopular, the opposition party can make deep inroads in states that favor the president, even if that seems unlikely a priori. In Montana, Bush carried the state by 20 points in 2004, but Jon Tester (D) knocked off three-term Sen. Conrad Burns (R) by 1 point. In Ohio, which Bush won by 2 points, Sherrod Brown (D) crushed two-term Sen. Mike DeWine (R) by 12 points. Democrats in all but Rhode Island overperformed their baselines by 9 to 21 points. That's about what it will take this year. (V)