As an adjective:
* The isolationist senator opposed any involvement in foreign wars.
* The country's isolationist policies kept it out of the global economic system.
* The isolationist views of the group were not shared by the majority of the population.
As a noun:
* The isolationist argued that the country should focus on its own problems instead of getting involved in international affairs.
* The political party was accused of being an isolationist group.
* The isolationist movement gained momentum after the devastating war.
As part of a phrase:
* The country pursued an isolationist foreign policy.
* The political party adopted an isolationist stance on trade agreements.
* The country's isolationist tendencies were a result of its history.
Remember: "Isolationist" can have a negative connotation, implying a rejection of international cooperation or a withdrawal from the world.