Why Maine stopped being a Republican stronghold in the 1960s and 70s is something I can't answer
Let's have that be the question we focus on so we can stop this non-constructive Verily-Gustaf argument. What caused Maine to become more Democratic than New Hampshire and what factors (beyond the fact that this situation has been the case since the 1960s or 70s which Verily has verily (sp?) pointed out) have helped it (Maine being more Democratic than New Hampshire) stay that way? I have pointed out that Maine didn't have the Manchester Union Leader (I forgot to mention the anti-tax or at least anti-income tax pledge I've read it pressed every candidate for Governor and the General Court to sign) and that postmaterialism (or in other words, a quasi-socialist (not meant to be a negative, that's up to you) mindset beyond simply perceived self-interest voting of the lower classes, union workers and state employees (again, not stated as a negative, particularly for the less well off, although people can and will argue day and night over whether it's shameful for state employees and those who might depend on welfare programs or a higher minimum wage and such - for those voters to vote for people who will keep, increase those benefits or jobs) ) and eventually what conservatives probably mean by latte liberalism were allowed to take root. Others have mentioned the French Canadian heratige of parts of Maine. Let's continue, or at least let's not keep arguing over the same old thing (the relevance of Maine's having voted more Democratic than New Hampshire since the 60s or 70s).
Your non-constructive. 
The point is that Maine used to be more Republican. When that changed, in the 60s, tradition couldn't have been the reason. Those few decades aren't enough to constitute a tradition, IMO.
My argument isn't about tradition, it's about infrastructure. Having a powerful local party counts for at least 5-10 points in any and every race.
