How did the united states break with its traditional approach to international affairs

Most white northerners viewed blacks as inferior. Northern states severly limited the rights of free African Americans and discouraged or prevented the migration of more. There was a minority of northerners called abolitionists who were vocal about ending slavery. They opposed slavery in the new territories because they were sick and tired of the South having a majority in the legislative and executive branch. Because of the 3/5s compromise, the South was able to get an upper hand at representation. As the new territories opened up, the North wanted the Wilmot Proviso. Hope this helps! Mark please!