Why Unpopular In Parties Get Slaughtered
By 
Good Yglesias post on why the Moore loss portends disaster for Republicans, even though Jones actually winning rather than merely keeping it closer than you would expect was lucky:
In the Alabama race, Senate Republicans suffered fundamentally from bad timing.
If the allegations of sexual misconduct against Roy Moore had surfaced during the primary, he likely would have lost to either Luther Strange or Mo Brooks, either of whom likely would have beaten Jones. If the allegations about Moore’s misconduct had surfaced after the general election, he might have been forced from office, but Alabama’s Republican governor would have appointed his replacement. Having this information come out during the window between the primary and the general election was a fluke, and absent that fluke, it’s hard to imagine Jones winning.
That said, Republicans have spent the past year acting as if a narrow — and extremely flukey — Trump Electoral College win made him an unstoppable man of destiny.
Alabama is a reminder that luck can cut in either direction. It’s also the case that to an extent, Democrats made their own luck in Alabama by recruiting a very strong candidate in Doug Jones at a time when the race seemed impossible to win. The freakishly large number of Democrats who want to run for office in 2018 is an indication that Democrats will be able to take advantage of whatever good luck comes their way next year, with decent candidates in the field almost everywhere.
Meanwhile, though Trump’s decision to hew to ideological orthodoxy has pleased GOP congressional leaders, those leaders are, themselves, unpopular. And in doing so, Trump has ditched most of the economic populism that helped him win white working-class crossover voters without ditching any of the bizarre personal behavior that cost him white college graduate crossover voters.
Structural conditions matter, and candidate quality matters. And the two are not fully independent variables — the combination of the Republicans being the incumbent party with an extremely unpopular president and an almost impossibly unpopular policy agenda will make it a lot easier for the Democrats to recruit good candidates (while Republicans have a much harder time, while also having incumbents step down.) And while gerrymandering is a powerful tool in a typical election if the wave gets big enough it makes you even more vulnerable than it could be otherwise. You might think that a party in this position would pass a tax cut that serviced their mass constituents as well as their donors, but they’re going solely with the latter. And now, they’ve lost their 2018 firewall in the Senate.
In related news:
Cory Gardner is already recruiting Jones to switch parties pic.twitter.com/rQecr8ozw7
— Ben Jacobs (@Bencjacobs) December 13, 2017
“Doug! How are ya? Look, I have an amazing opportunity. You can join the Republican conference, whose leadership backed a deranged neoconfederate child molester because he would make it easier to pass a policy agenda that’s less popular than cancer of the rectum. Hello? Doug?”