The answer would be Logos. This is a kind of appeal to reason or logic. When using this kind of appeal, it uses facts and evidence to persuade a the listener of the strength of your argument. This is different from pathos, which is an appeal to the emotions, whereas, ethos, from its word, uses ethics or credibility of the person making the argument.
The Kansas-Nebraska Act passed May 30, 1854 allowed the territories of Kansas & Nebraska to decide themselves wether or not they would adopt slavery. This infuriated the Northerns who followed the Missouri Compromise and the Southerns pushed for slavery in the territories. Due to this two legislation in Kansas many people opposed each other giving Kansas the nickname "Bleeding Kansas" President Pierce had to send in Federal Troops to cease the civil unrest.
Too summarize the Kansas-Nebraska act stated that the territories could vote wether or not they should adopt slavery.
It was better than the English and the Spanish because the french treated them better
Reformers would not have demanded change because British and French economies are more stable