Long before the Trump presidency spiraled completely out of control, many Americans comforted themselves by asserting we were not in a civil war. As we sift through the debris left by the insurrectionists who stormed the Capitol on Jan. 6 — and anticipate what is likely to come — we ignore at our peril the cautionary tale of the last Civil War and what followed it.

Today’s reunification efforts, led by Republicans who call for healing just days after the riot, mask challenges much as similar calls did in 1865. Then, as now, we were a country divided by different values, including a contingent willing to use violence and anti-democratic means to accomplish its goals. Healing isn’t possible until those challenges are placed squarely on the table and addressed. Nor is it possible when those who seek to thwart the Constitution aren’t held accountable.

History reminds us that avoiding this difficult work only pushes division and violence into the future.

The very goals of the Union war effort and Reconstruction were to preserve the union and reunify, which meant ending slavery and bringing the individuals and states of the Confederacy back into the national fold. But when Gen. Ulysses S. Grant compelled the surrender of Robert E. Lee’s army at Appomattox in 1865, Grant’s primary goal was merely to end the fighting. There was no co-signed treaty dictating the terms of peace or laying out the process of reunion. Instead, Grant paroled Lee’s army and sent them home on the promise that they would not be disturbed by U.S. officials so long as they agreed to henceforth obey the law.

Grant, worried about the dispersal of rebel soldiers across the South and the potential for guerrilla warfare that might follow, insisted that paroling as many Confederates as quickly as possible would serve as the best means for achieving peace and reconciliation. Retribution, he believed, would lead to continued warfare. But in the weeks and months that followed, many Northerners rebuked Grant for his magnanimous surrender terms.

Though President Andrew Johnson at first called to punish the treasonous, he then offered, only weeks after taking office, forgiveness rather than punishment. On May 29, 1865, he issued his first proclamation of pardon, which conferred amnesty to all participants in the rebellion who took an oath promising two things: to support and defend the Constitution, and to support all laws concerning the emancipation of slaves. Confederates did not need to rebuke their cause or denounce their past actions, only promise future loyalty. Johnson’s policy opened the door for the vast majority of Confederates to regain their legal and political rights as Americans.

Johnson and Grant believed that the country could heal if it looked forward rather than backward. But this approach only helped seed further resistance. Even at Appomattox, Lee fanned the flames of division when he praised Confederates for devotion to their country. As one Virginia newspaper reassured its readers, “We are still proud of our country [aye, if possible, prouder than ever], and still love it with devotion intensified by her misfortune.”