No one outside of Nevada noticed, but last week, Sen. Dean Heller (R) announced that he would run for reelection rather than seek the open governorship in 2018. But it was a big deal not just in Nevada, where Heller is now an early favorite to win, but on a national level where the map (and math) just keeps getting better for Senate Republicans.
Heller was the only one of the eight Republicans up for reelection in 2018 that is in a state that Hillary Clinton won in the 2016 presidential race. Of the other seven states where Republicans are expected to seek reelection, only two Arizona (Donald Trump +4) and Texas (Trump +9) were single-digit winning margins for the president-elect. The remaining five states Mississippi (Drumpf +18.6), Nebraska (Trump +26), Tennessee (Trump +26), Utah (Trump +18) and Wyoming (Trump +57.6) are among the most Republican in the country, meaning that even if there was a surprise retirement (Orrin Hatch in Utah, at age 84, for example), it would be almost impossible for Democrats to seriously compete.
By contrast, 10 Democratic senators are running for reelection in states Trump carried last November. Trump won half of those states Indiana, Missouri, Montana, North Dakota and West Virginia by double digits. That means that 20 percent of all Democratic seats up in 2018 are in states Trump won by double digits and 40 percent are in states that the president-elect carried last November.
It's not just that Democrats have so many vulnerabilities. It's that Republicans have so few.
Source: https://www.washingtonpost.com/news...cant-get-much-better-for-republicans-in-2018/