Abraham Lincoln’s assassination on April 14, 1865, confronted the American public with urgent political challenges that would shape the trajectory of the post-Civil War United States. But a religious controversy that erupted during the subsequent weeks of national mourning would raise enduring social and moral questions about what it means to be both deeply patriotic and religiously observant in America.

Shortly after Lincoln’s murder, President Andrew Johnson declared a “day of humiliation and mourning,” upon which he recommended that his fellow citizens across the country gather in their respective places of worship to lament the late president’s tragic demise. But in doing so, Johnson had unwittingly created a significant dilemma for American Jews. His chosen date—June 1, 1865—happened to coincide with the Jewish holiday of Shavuot, which commemorates God’s revelation of the Law at Mount Sinai.

Today, the holiday is popularly observed among Orthodox and various traditionalist Jews but largely ignored by others. In an article for the American Israelite newspaper, leading 19th-century Reform Rabbi Isaac Mayer Wise described a similar state of affairs in mid-19th-century America. (Later in the century, American Reform communities increasingly began to celebrate Shavuot as a confirmation day.) But traditionalist Jewish congregations, including some of the most prominent synagogues in the nation, had long observed Shavuot by reading customary mystical and liturgical Jewish texts, many still recited today, that reinforced fealty to the Torah’s commandments—and these congregations often saw large crowds on Shavuot, even inviting non-Jewish dignitaries to attend. So while not all American Jews observed Shavuot at the time of Lincoln’s assassination, those who did considered it one of Judaism’s happiest occasions, upon which Jewish law prohibits any expressions of mourning.

Many American Jews in 1865, therefore, faced what seemed like a stark choice between duty to country and duty to God—between patriotism and piety. As Shavuot drew near, Jewish writers, political activists, and spiritual leaders throughout the United States began in earnest to weigh in on the matter. Out of their respective solutions emerged two different models for how faith communities should serve the public square: compliance and conviction.