In his 1944 message to Congress, Roosevelt said that "our rights to life and liberty"—the negative liberty to which Obama referred, had "proved inadequate to assure us equality in the pursuit of happiness." He claimed that "In our day these economic truths have become accepted as self-evident. We have accepted, so to speak, a second Bill of Rights." This bill of rights included the right to a job, the right to food and recreation, the right to adequate farm prices, the right to a decent home, the right to medical care, and the right to a good education.
Of course, these are not "rights" at all—not in the sense that the framers and ratifiers of the Declaration of Independence and Constitution used the term--but entitlements. From the founding until the twentieth century, the American regime assumed that government's purpose was to secure pre-existing natural rights—such life, liberty, property, or association. Everyone can exercise such rights simultaneously; nobody's exercise of his own rights limits anyone else's similar exercise. Your right to life or to work or to vote does not take anything away from anyone else. We can all pursue happiness at once. Entitlements, on the other hand, require someone else to provide me with the substantive good that the exercise of rights pursues. The right to work, for example, is fundamentally different from the right (entitlement) to a job; the right to marry does not entitle me to a spouse; the right to free speech does not entitle me to an audience.