The Second Party System may be the least understood of the three, yet it will have two elections in this list – of course, both hastened its demise. The first one makes the list largely because of where it took place: the ultimate redoubt of conservative Whiggery, Massachusetts. Back then, the Whigs were the party of big-government corporatism, so mid-19th century conservatives naturally did far better in Massachusetts than their 21st Century counterparts. In fact, the Whigs only lost two elections in total in the Bay State from 1830 to 1850. Both were to antislavery Democrat Marcus Morton (for Governor), and both times Morton won by exactly one vote (one voter in 1939, and one defecting Whig state senator in 1842).
Then came 1850. In the first election after the Compromise of that year, most of the focus was on the South, where it proved a serious impediment to disunionists. Even the Whigs, who were racked by division on the matter in the North, held there own in the slave states. But in Massachusetts, the Whig coalition completely broke down. As Daniel Webster moved to Secretary of State in Millard Fillmore’s Administration, a coalition of Free Soilers and Democrats sent Robert Rantoul, Jr., to Washington to replace him – the only Democrat to represent Massachusetts in the Senate between 1818 and 1918. A Democrat was also installed as Governor, while (eventually) Charles Sumner replaced Rantoul.
It is Sumner’s election that makes the grade. It revealed that antislavery voters could work with Democrats to break a previous impenetrable Whig lock. In the short term, it so badly damaged the pro-Compromise forces in the Whig Party that Fillmore became the first incumbent president in American history to be denied his party’s nomination. The Whigs instead rejected the Compromise in their platform and ran General Winfield Scott; the resulting 1852 landslide spelled the beginning of the end of the Whig Party, especially in the South. Politics in Massachusetts would be in flux for most of the decade, a harbinger of northern politics in general.
This is due to the larger, long-term impact of the Sumner shocker: antislavery voters were at long last the swing vote they craved to be. The Liberty and Free Soil parties had previously tried and failed to pull this off, but they hit the jackpot in 1850. From then on, both parties knew that antislavery voters could be part of their local coalitions, and they strived for those voters. Thus did the northern parties feel compelled to address issues that no southern politician even wanted to hear, putting enormous strain on the Democrats and ending the Whigs entirely.
None of this was expected (although antislavery politicians certainly hoped for it) before Massachusetts broke its own mold in 1850. All of it was in play afterwards.
