March 15, 1820 was the day that Maine joined the Union as part of the Missouri Compromise engineered by House Speaker Henry Clay of KY. That legislation stopped northern attempts to prohibit slavery’s expansion by admitting Missouri as a slave state. But Mainers were upset that their state was used to legalize slavery in any way. Abolitionism grew strongly in the state for the next 40 years, and natives of Maine proved instrumental in the ultimate abolishment of slavery, as historian Heather Cox Richardson explained in her daily “Letter from an American.”
Thomas Jefferson had long brooded about America’s “birth defect” — slavery. “Indeed I tremble for my country when reflect that God is just: that his justice cannot sleep for ever: that considering numbers, nature and natural means only, a revolution of the wheel of fortune, an exchange of situation, is among possible events: that it may become probable by supernatural interference!” he wrote in Notes on the State of Virginia.
The Missouri “compromise” worried him greatly about the direction of the country. “Like a fire bell in the night, (it) awakened and filled me with terror,” he wrote a friend. “I considered it at once as the knell of the Union. It is hushed indeed for the moment, but this is a reprieve only, not a final sentence.”
Richardson wrote: “Mainers were angry that their statehood had been tied to the demands of far distant slave owners, and that anger worked its way into the state’s popular culture. The opening of the Erie Canal in 1825 meant that Maine men, who grew up steeped in that anger, could spread west. And so they did.”
His younger brother Owen, who “saw Elijah shot and swore his allegiance to the cause of abolition.” He was elected to the Illinois legislature, and became friends with Abraham Lincoln.
Israel and Elihu Washburn, who both served in Congress and voted to overturn the Missouri Compromise by passing the Kansas-Nebraska Act.
Hannibal Hamlin, Senator from Maine and a former Democrat. He could help persuade other anti-slavery Democrats to abandon the party.
They helped create a new political party, the anti-slavery Republicans.
“In 1859, Abraham Lincoln would articulate an ideology for the party, defining it as the party of ordinary Americans standing together against the oligarchs of slavery, and when he ran for president in 1860, he knew it was imperative that he get the momentum of Maine men on his side. In those days Maine voted for state and local offices in September, rather than November, so a party’s win in Maine could start a wave. “As Maine goes, so goes the nation,” the saying went.” — Richardson wrote.
Lincoln chose Hamlin as his vice president, partly for geographical balance.