The us republican party mostly includes members who are

The US Republican Party mostly includes members who are conservative.

Explanation:

The Republican party is the most conservative of the two great parties of the country. Ideologically speaking, it could be classified as a "lay conservative" to distinguish it from the Christian Democratic parties that embody the right-wing in other Western nations.

In the economic aspect, its doctrine is fiscal conservatism: defender of the free market and enemy of the intervention of the State. That is why Republicans consider themselves the strongest advocates of American laissez faire.