On the origins of the term Michigander...
Michigander is considered pejorative by some due to the circumstances under which the term was coined, but others perceive no such negative connotation. Michigander is attributed to Abraham Lincoln, coining it when he was a Whig representative in Congress. On July 27, 1848, Lincoln made a speech against Lewis Cass, who had been a long-time governor of the Michigan Territory. Cass was then running for president on a " popular sovereignty" platform that would have let states that were conquered in the Mexican-American War decide whether to legalize slavery. Lincoln accused the Democrats of campaigning on the former President Andrew Jackson's coattails by exaggerating their military accomplishments.
But in my hurry I was very near closing on the subject of military tails before I was done with it. There is one entire article of the sort I have not discussed yet; I mean the military tail you Democrats are now engaged in dovetailing onto the great Michigander [i.e. Lewis Cass].
Lincoln thus combined Michigan with gander to form a nickname that made Cass sound foolish like a goose. Michiganders would go on to vote for Lincoln for President twice in 1860 and 1864.