Historians criticized proposed revisions to the Texas social studies curriculum Tuesday, saying that many of the changes are historically inaccurate and that they would affect textbooks and classrooms far beyond the state's borders.

The changes, which were preliminarily approved last week by the Texas board of education and are expected to be given final approval in May, will reach deeply into Texas history classrooms, defining what textbooks must include and what teachers must cover. The curriculum downplays the role of Thomas Jefferson among the founding fathers, questions the separation of church and state and says that the U.S. government was infiltrated by communists during the Cold War.

Because the Texas textbook market is so large, books assigned to the state's 4.7 million students often rocket to the top of the market, decreasing costs for other school districts and leading them to buy the same materials.