Eight national and local organizations that deal in education and freedom of speech on Wednesday sent to the Jefferson County School Board a letter voicing their opposition to a proposed review of the curriculum for AP U.S. history.

Read the National Coalition Against Censorship letter to the Jefferson County School Board

“Decisions about instructional materials should be based on sound educational grounds, not because some people do or do not agree with the message, ideas or content of a particular book or lesson,” the letter says.

The groups, which include the National Coalition Against Censorship and the American Civil Liberties Union of Colorado, said they found aspects of the proposed committee “deeply problematic.”

The letter was sent one day before the board is set to discuss the proposal, which has been at the center of three weeks of protests in the county. The meeting is scheduled for 5:30 p.m. Thursday.

“We strongly urge you to adopt policies and procedures that focus, not on molding patriots or citizens in a particular image, but on educating students to be informed, knowledgeable, thoughtful and engaged participants in their communities,” the letter said.

Other organizations signing on to the letter include the National Council for the Social Studies, National Council of Teachers of English, American Booksellers Foundation for Free Expression, PEN American Center, Comic Book Legal Defense and Education Fund and Society of Children’s Book Writers and Illustrators.

Last month, school board member Julie Williams proposed the committee to create a curriculum that promotes “positive aspects” of U.S. history while avoiding the encouragement of “civil disorder, social strife or disregard for the law.”

The school board tabled the proposed committee and said it was considering significant cuts and changes to the proposal.

Jesse Paul: 303-954-1733, jpaul@denverpost.com or twitter.com/JesseAPaul