Among these unalienable rights, as proclaimed in that great document, is the right of men to pursue their happiness, by which is meant the right to pursue any lawful business or vocation, in any manner not inconsistent with the equal rights of others, which may increase their prosperity or develop their faculties, so as to give to them their highest enjoyment. The common business and callings of life, the ordinary trades and pursuits, which are innocuous in themselves, and have been followed in all communities from time immemorial, must therefore be free in this country to all alike upon the same conditions. The right to pursue them, without let or hinderance, except that which is applied to all persons of the same age, sex, and condition, is a distinguishing privilege of citizens of the United States, and an essential element of that freedom which they claim as their birthright. It has been well said that 'THE PROPERTY WHICH EVERY MAN HAS IN HIS OWN LABOR, AS IT IS THE ORIGINAL FOUNDATION OF ALL OTHER PROPERTY, SO IT IS THE MOST SACRED AND INVIOLABLE. The patrimony of the poor man lies in the strength and dexterity of his own hands, and to hinder his employing this strength and dexterity in what manner he thinks proper, without injury to his neighbor, is a plain violation of this most sacred property. It is a manifest encroachment upon the just liberty both of the workman and of those who might be disposed to employ him. . . The right to follow any of the common occupations of life is an inalienable right, it was formulated as such under the phrase 'pursuit of happiness' in the declaration of independence, which commenced with the fundamental proposition that 'all men are created equal; that they are endowed by their Creator with certain inalienable rights; that among these are life, liberty, and the pursuit of happiness.' This right is a large ingredient in the civil liberty of the citizen. To deny it to all but a few favored individuals, by investing the latter with a monopoly, is to invade one of the fundamental privileges of the citizen, contrary not only to common right, but, as I think, to the express words of the constitution. It is what no legislature has a right to do; and no contract to that end can be binding on subsequent legislatures. . . BUTCHERS' UNION CO. v. CRESCENT CITY CO., 111 U.S. 746 (1884)