Looking closely at the Maryland numbers reveals a fascinating picture: Hogan didn't beat Brown because people love Hogan. He beat Brown because voters weren't particularly enthusiastic about Brown, and didn't come vote.
It is fair to describe Martin O'Malley's 2010 victory over former Governor Bob Ehrlich as a thumping. O'Malley won 56.2%-41.8%. Let's use it as a baseline to inquire whether Brown's loss was because people switched allegiance to the Republicans, or because former O'Malley voters just stayed home and voted for no one at all.
It was the latter: O'Malley voters stayed home. Let's see how we know that, below the fold.
Hogan got a little less than 71,000 more votes than Ehrlich did. But O'Malley got more than 274,000 more votes than Brown did. In other words, despite Maryland's population increase since 2010, more than 200,000 more people voted for governor in 2010 than in 2014. If all the people who voted for O'Malley, but didn't vote at all this time, had come out and voted for Brown, Brown would have won, even if Hogan didn't get one vote fewer.
The results are particularly profound if you look at the absolute vote totals in the biggest, bluest counties:
In Montgomery County, Hogan got 1,512 more votes than Ehrlich did. O'Malley got 47,435 more than Brown.
In Prince George's County, Hogan got 4,295 more votes than Ehrlich did. O'Malley got 29,952 more than Brown.
In Baltimore City, Hogan got 3,085 more votes than Ehrlich did. O'Malley got 33,977 more than Brown.
There is one, and only one lesson to draw from this: Democratic-leaning Marylanders were uninspired and stayed home. Hogan doesn't have a mandate, and people aren't called to his message. They just didn't care, or were unenthused by Brown.
Turnout matters.
[A methodological note: I have been using figures from the Maryland State Board of Elections website:2014; 2010. Hogan's been reported to get a considerably higher total in some press reports, as well as some diaries here; the difference seems to be that the New York Times gave Hogan 193,970 votes in Anne Arundel County, whereas the Board of Elections gave him only 113,970. Given the one-digit difference and the identical vote totals for Brown, I am assuming a transcription error, and also that the Board of Elections' figure is correct--the NYT figure would mean that there were more votes cast in Anne Arundel County than in Montgomery, despite having less than 2/3 the population.]