I'm not going to explain this to the level of profession befitting an official post on the SalC thread or anything, but here's my notes on Maine's founding.
So, like IOTL, Maine used to be part of Massachusetts. Of course, some people wanted independence from Massachusetts, and a number of referendums were held. The issue here is that there's a movement of people, on both sides of separatism and unionism, who think that, when the results of a referendum are announced, it goes into effect. This is largely championed by this one particular bloke, who is a fervent campaigner for Mainer independence.
The first referendum is in 1792. It overall fails, but in towns that vote for independence, there is light rioting as people try to kick out town officials under the belief that their offices are now vacant due to the nonexistent change in power. This is righted.
The second referendum is in, what, 1806? That sounds about right. That or 1808. Anyway, in this referendum, the yes vote does win, and Mister Instant Referendum starts a bit of a civil war. Independence for Maine is thus called off. This happens multiple times over the next decade, and finally, in 1820, Massachusetts evacuates all civil authority in advance of the referendum, and so a full-on civil war breaks out.
I'm glad I'm typing this out and not saying it in person, because I'm not sure I can say this to somebody with a straight face: the war is very civil, and so everybody is very polite and nobody dies in battle. It's still a goddamn mess, though, and it takes up to a year and a half for the state of Maine to properly set itself up in any way. The first couple of elections are contested three ways between the two national factions and the followers of Mister Instant Referendum, who blasts both of the other parties as full of foreign Massachusetts agents for having participated in the Massachusetts government. Then the party system collapses in some way or another. I don't know what Maine gets up to after that, though they did abolish the year 1851.