What group of people actively sought to end the institution of slavery?

The group of people who actively sought to end the institution of slavery were abolitionists. Abolitionists were individuals and groups who campaigned against slavery, advocating for its complete eradication. This movement gained significant momentum in the United States during the 19th century, with influential figures such as Frederick Douglass and Harriet Tubman leading the charge. Abolitionists utilized various methods to promote their cause, including publishing antislavery literature, delivering speeches, and participating in underground railroad activities to help enslaved individuals escape to freedom.

While Unionists were primarily focused on preserving the Union during the Civil War and Reformists sought to improve various aspects of society, including education and women's rights, they did not specifically concentrate solely on ending slavery. Nationalists, on the other hand, were primarily concerned with the interests and independence of their nation, which did not inherently include the abolition of slavery. Thus, abolitionists distinctively represent those who specifically aimed to eliminate the practice of slavery altogether.