Final answer:
The Lincoln-Douglas debates in 1858 are significant because they shaped public opinion on slavery and elevated Abraham Lincoln's national profile, paving the way for his presidential bid.
Step-by-step explanation:
The major significance of the famed Lincoln-Douglas debates in 1858 was that they shaped public opinion on the issue of slavery. These debates were a series of seven public encounters between Abraham Lincoln and Stephen Douglas, dealing with the issue of slavery and its expansion. Their content was widely published and keenly followed across the nation, which significantly raised Lincoln's profile.
The debates did not lead to Douglas's election as president or result in the immediate abolition of slavery nor were they merely a display of the candidates' charisma. Instead, they highlighted the differences between Democrats and Republicans on the subject of slavery and helped propel Abraham Lincoln into the national political spotlight, setting the stage for his successful presidential campaign in 1860.