The evolution of CST is studied in this chapter, in relation to the three distinct main matters denoted by the ambiguous term “globalization”: (1) the increasing interconnections and interactions between people all over the world and the resultant interdependencies that reinforce other interdependencies such as exhaustion of natural resources, transfer of resources, money, means of destruction, people, vulnerability to pollution and environmental degradation, and so on; (2) proposals to respond to all that (and to “dangerous anthropogenic global warming”) by establishing global law and institutions of governance; (3) proposals to facilitate migration from poorer countries to richer ones for the sake of a better life for the migrants (and their relatives or other dependents). Neither CST nor the rest of Catholic moral doctrine has doubted that states and peoples have a responsibility to respect other states and peoples and the common good of human persons worldwide; or that individuals and groups have, in dire necessity, rights to seek and find refuge in nearby safe states for at least the duration of that danger and necessity. But beyond these basics, there have been developments, in various directions. And this chapter traces some main developments over the past 125 years.