AUSTIN, Tex. — After three days of turbulent meetings, the Texas Board of Education on Friday approved a social studies curriculum that will put a conservative stamp on history and economics textbooks, stressing the superiority of American capitalism, questioning the Founding Fathers’ commitment to a purely secular government and presenting Republican political philosophies in a more positive light.

The vote was 10 to 5 along party lines, with all the Republicans on the board voting for it.

The board, whose members are elected, has influence beyond Texas because the state is one of the largest buyers of textbooks. In the digital age, however, that influence has diminished as technological advances have made it possible for publishers to tailor books to individual states.

In recent years, board members have been locked in an ideological battle between a bloc of conservatives who question Darwin’s theory of evolution and believe the Founding Fathers were guided by Christian principles, and a handful of Democrats and moderate Republicans who have fought to preserve the teaching of Darwinism and the separation of church and state.

Since January, Republicans on the board have passed more than 100 amendments to the 120-page curriculum standards affecting history, sociology and economics courses from elementary to high school. The standards were proposed by a panel of teachers.