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 10-5 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. But in the digital age, 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 Charles Darwin's theory of evolution and believe that the Founding Fathers were guided by Christian principles, and a handful of Democrats and GOP moderates who have fought to preserve the teaching of Darwinism and the separation of church and state.

Since January, board Republicans 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.

"We are adding balance," Don McLeroy said after the vote. "History has already been skewed. Academia is skewed too far to the left."