This law, which allowed territories to decide the fate of slavery based on popular sovereignty, unintentionally had the effect of increasing tensions between pro-slavery and antislavery forces as they rushed west and had violent clashes over control of territory.

Respuesta :

For the answer to the question above, I believe this is the "Kansas-Nebraska Act." This law, which allowed territories to decide the fate of slavery based on popular sovereignty, unintentionally had the effect of increasing tensions between pro-slavery and antislavery forces as they rushed west and had violent clashes over control of territory. It was the Kansas-Nebraska Act.
I hope this helps