What was the first presidential election that showcased a Republican candidate against a Democrat?

The first presidential election that featured a Republican candidate running against a Democrat was in 1856. This election is significant because it marked the emergence of the Republican Party as a major political force in the United States. The Republican candidate, John C. Frémont, was running against James Buchanan, the Democratic candidate who eventually won the election.

The 1856 election was crucial as it demonstrated the growing divide in the country over issues such as slavery, which was a central concern of the newly formed Republican Party, advocating for its restriction in new territories. The election highlighted the shift in American politics leading up to the Civil War, making the 1856 election a pivotal moment in U.S. history as it set the stage for future political conflicts and the rise of sectionalism.

While the other options represent significant elections in their own right, they do not mark the first instance of a Republican contesting against a Democrat, which is why the focus on 1856 is particularly important in this context.