In 1831, Tocqueville obtained from the July Monarchy a mission to examine prisons and penitentiaries in the United States and proceeded there with his lifelong friend Gustave de Beaumont. While he did visit some prisons, Tocqueville traveled widely in the United States and took extensive notes about his observations and reflections. He returned within nine months and published a report, but the real result of his tour was De la démocratie en Amérique, which appeared in 1835. Beaumont also wrote an account of their travels in Jacksonian America: Marie or Slavery in the United States (1835). During this trip, he made a side trip to Montreal and Quebec City in Lower Canada from mid-August to early September 1831.

In 1835, Tocqueville made a journey through Ireland. His observations provide one of the best pictures of how Ireland stood before the Great Famine (1845–1849). The observations chronicle the growing Catholic middle class and the appalling conditions in which most Catholic tenant farmers lived. Tocqueville made clear both his opposition to aristocratic power and his affinity for his Irish co-religionists.

In Democracy in America, published in 1835, Tocqueville wrote of the New World and its burgeoning democratic order. Observing from the perspective of a detached social scientist, Tocqueville wrote of his travels through the United States in the early 19th century when the Market Revolution, Western expansion and Jacksonian democracy were radically transforming the fabric of American life.

Tocqueville explicitly cites inequality as being incentive for the poor to become rich and notes that it is not often that two generations within a family maintain success and that it is inheritance laws that split and eventually break apart someone’s estate that cause a constant cycle of churn between the poor and the rich, thereby over generations making the poor rich and the rich poor. He cites protective laws in France at the time that protected an estate from being split apart among heirs, thereby preserving wealth and preventing a churn of wealth such as was perceived by him in 1835 within the United States.

Tocqueville believed that the American jury system was particularly important in educating citizens in self-government and rule of law. He often expressed how the civil jury system was one of the most effective showcases of democracy because it connected citizens with the true spirit of the justice system. In his 1835 treatise Democracy in America, he explained: “The jury, and more especially the civil jury, serves to communicate the spirit of the judges to the minds of all the citizens; and this spirit, with the habits which attend it, is the soundest preparation for free institutions. […] It invests each citizen with a kind of magistracy; it makes them all feel the duties which they are bound to discharge toward society; and the part which they take in the Government”.

Tocqueville, who despised the July Monarchy (1830–1848), began his political career in 1839. From 1839 to 1851, he served as member of the lower house of parliament for the Manche department (Valognes). He sat on the centre-left, defended abolitionist views and upheld free trade while supporting the colonisation of Algeria carried on by Louis-Philippe’s regime.

Apart from North America, Tocqueville also made an observational tour of England, producing Memoir on Pauperism. In 1841 and 1846, he traveled to Algeria. His first travel inspired his Travail sur l’Algérie, in which he criticized the French model of colonisation based on an assimilationist view, preferring instead the British model of indirect rule, which avoided mixing different populations together. He went as far as openly advocating racial segregation between the European colonists and the Arabs through the implementation of two different legislative systems (a half century before implementation of the 1881 Indigenous code based on religion).

French historian of colonialism Olivier LeCour Grandmaison has underlined how Tocqueville (as well as Jules Michelet) used the term “extermination” to describe what was happening during the colonization of Western United States and the Indian removal period. Tocqueville thus expressed himself in 1841 concerning the conquest of Algeria:

Tocqueville’s views on the matter were complex. Although in his 1841 report on Algeria he applauded Bugeaud for making war in a way that defeated Abd-el-Kader’s resistance, he had advocated in the Two Letters that the French military advance leave Kabylie undisturbed and in subsequent speeches and writings he continued to oppose intrusion into Kabylie.

In opposition to Olivier Le Cour Grandmaison, Jean-Louis Benoît said that given the extent of racial prejudices during the colonization of Algeria, Tocqueville was one of its “most moderate supporters”. Benoît said that it was wrong to assume Tocqueville was a supporter of Bugeaud despite his 1841 apologetic discourse. It seems that Tocqueville modified his views after his second visit to Algeria in 1846 as he criticized Bugeaud’s desire to invade Kabylie in an 1847 speech to the Assembly.

In 1847, he sought to found a Young Left (Jeune Gauche) party which would advocate wage increases, a progressive tax, and other labor concerns in order to undermine the appeal of the socialists. Tocqueville was also elected general counsellor of Manche in 1842 and became the president of the department’s general council between 1849 and 1852; he resigned as he refused to pledge allegiance to the Second Empire. According to one account, Tocqueville’s political position became untenable during this time in the sense that he was mistrusted by both the left and right and was looking for an excuse to leave France.

In his 1847 “Report on Algeria”, Tocqueville declared that Europe should avoid making the same mistake they made with the European colonization of the Americas in order to avoid the bloody consequences. More particularly he reminds his countrymen of a solemn caution whereby he warns them that if the methods used towards the Algerian people remain unchanged, colonization will end in a blood bath.

In 1855, Tocqueville wrote the following text published by Maria Weston Chapman in the Liberty Bell: Testimony against Slavery:

Against this image of Tocqueville, biographer Joseph Epstein has concluded: “Tocqueville could never bring himself to serve a man he considered a usurper and despot. He fought as best he could for the political liberty in which he so ardently believed—had given it, in all, thirteen years of his life [….]. He would spend the days remaining to him fighting the same fight, but conducting it now from libraries, archives, and his own desk”. There, he began the draft of L’Ancien Régime et la Révolution, publishing the first tome in 1856, but leaving the second one unfinished.

In 1856, Tocqueville published The Old Regime and the Revolution. The book analyzes French society before the French Revolution—the so-called Ancien Régime—and investigates the forces that caused the Revolution.

A longtime sufferer from bouts of tuberculosis, Tocqueville would eventually succumb to the disease on 16 April 1859 and was buried in the Tocqueville cemetery in Normandy.

The above is often misquoted as a slavery quote because of previous translations of the French text. The most recent translation by Arthur Goldhammer in 2004 translates the meaning to be as stated above. Examples of misquoted sources are numerous on the internet, but the text does not contain the words “Americans were so enamored by equality” anywhere.

Tocqueville was quoted in several chapters of Toby Young’s memoirs How to Lose Friends and Alienate People to explain his observation of widespread homogeneity of thought even amongst intellectual elites at Harvard University during his time spent there. He is frequently quoted and studied in American history classes. Tocqueville is the inspiration for Australian novelist Peter Carey in his 2009 novel Parrot and Olivier in America.