Tocqueville thought the conquest of Algeria was important for two reasons: first, his understanding of the international situation and France's position in the world, and, second, changes in French society. Tocqueville believed that war and colonization would "restore national pride, threatened", he believed, by "The gradual softening of social mores" in the middle classes. Their taste for "material pleasures" was spreading to the whole of society, giving it "an example of weakness and egotism". Applauding the methods of General Bugeaud, Tocqueville went so far to claim that "war in Africa is a science. Everyone is familiar with its rules and everyone can apply those rules with almost complete certainty of success. One of the greatest services that Field Marshal Bugeaud has rendered his country is to have spread, perfected and made everyone aware of this new science." Tocqueville advocated racial segregation in Algeria with two distinct legislations, one for European colonists and one for the Arab population. Such a two-tier arrangement would be fully realised with the 1870 Cremieux decree and the Indigenousness Code, which extended French citizenship to European settlers and Algerian Jews, whereas Muslim Algerians would be governed by Muslim law and restricted to a second-class citizenship. 
What did Tocqueville advocate for that came into effect in 1870?
Racial segregation in Algeria