The 1876 presidential election nearly reignited civil war.

Evidence

When the election of 1876 came in November, it was war at the polls, and Democrats stuffed ballot boxes across the South. By the morning of November 8, 1876, Democratic New York governor Samuel J. Tilden and Republican Ohio governor Rutherford B. Hayes were virtually tied in the electoral college. The presidential election’s outcome rested in the contested election returns of Louisiana and South Carolina. When a fifteen-member electoral commission handed Republicans the presidency, Democrats were outraged. In early 1877, both parties, and both regions, began planning for another Civil War. — Ibram X. Kendi, Stamped from the Beginning, 687