When Barack Obama announced his presidential candidacy on February 10, 2007, he did it in Springfield, Illinois, in the same place where Abraham Lincoln had made his historic challenge to slavery in June 1858. “A house divided against itself cannot stand,” Lincoln had declared, conveying his conviction that the union could no longer countenance the existence of a slave-owning South.

This speech, Obama said, was the basis of his candidacy: “And that is why, in the shadow of the Old State Capitol, where Lincoln once called on a divided house to stand together, where common hopes and common dreams still live, I stand before you today to announce my candidacy for President of the United States,” Obama said. But Obama had Lincoln’s speech exactly backwards. Lincoln wasn’t calling for a divided house to stay together. He was arguing against compromise with the slave South.

Obama recently invoked Lincoln again to justify his own penchant for compromise. At a speech at the University of Maryland on July 22, the president cited Lincoln’s Emancipation Declaration as an example of the kind of compromise that he also has to make today. “The Great Emancipator was making a compromise in the Emancipation Proclamation because he thought it was necessary in terms of advancing the goals of preserving the Union and winning the war,” Obama said. “So, you know what? If Abraham Lincoln could make some compromises as part of governance, then surely we can make some compromises when it comes handling our budget.”

Obama insisted that the declaration was a compromise because it didn’t address slavery in the border states allied with the North. But the Union was at war with the South, and the proclamation stripped the Confederate slave-owners of their right to own slaves. Lincoln didn’t say that they could own slaves if they agreed to return to the Union, or that they could own no more than six slaves. That would have been a compromise. Just as he had done in Springfield, Obama turned one of Lincoln’s uncompromising acts of courage into a justification for compromise.

THIS IS IMPORTANT because Obama may now be facing his own crisis of the Union. Over the last four decades, the Republican Party has transformed from a loyal opposition into an insurrectionary party that flouts the law when it is in the majority and threatens disorder when it is the minority. It is the party of Watergate and Iran-Contra, but also of the government shutdown in 1995 and the impeachment trial of 1999. If there is an earlier American precedent for today’s Republican Party, it is the antebellum Southern Democrats of John Calhoun who threatened to nullify, or disregard, federal legislation they objected to, and who later led the fight to secede from the union over slavery.