The Republican Party By definition, the Republican Party (also referred to as GOP, the ?Great Old Party?) is one of the two major political parties in the United States whose foundation is built on conservatism, focuses on national security, and has an economy led by the people. An economy ?led by the people? means that there is free market and enterprise with little interference from the government. The party dates all the way back to 1854 and was originally made up of northerners to oppose the spread of slavery.