I was reading through data. I found that, when comparing to the national average, in every election since 2008. Here is what I found. Note: EVEN means margin is within one percentage point of the national average. I round down. Presidential election years:
Year, Lean relative to nation 2008, EVEN 2012, R+9 2016, R+7
Midterm elections for House:
Year, Lean relative to nation 2010, R+12 2014, R+2 2018, EVEN
This is according to Wikipedia's entry for each election result. So, it seems that they are, since 2008, at least as likely to vote Republican.
Why is this? Is it because Democrats are more politically engaged despite describing themselves as moderate more than Republicans? Is it because independents are generally weary of progressives even though Bernie Sanders is one? Is it something else?