A Denver school board has refused to back off from a controversial planned review of the Advanced Placement history course, which would promote "patriotism" and "respect for authority" in American history, and has triggered protests from students and parents in the district.

The conservative-majority board of the Jefferson County Board of Education, which controls the curriculum for 84,000 students, voted to proceed with a review initiated by board member Julie Williams, which has sparked student walk-out and teacher sick-outs in almost all of the districts schools. 

Reuters cited opponents of the bill, who called it an attempt by the board to advance a conservative political agenda.

A report from the Associated Press described a tempestuous board meeting Thursday, where audience members yelled "resign" and "recall, recall". The two women on the board who oppose the conservative majority reportedly held their heads in their hands.

In an apparently conciliatory gesture to the opposition, the board voted to expand the membership on two existing curriculum review committees to include students, parents and administrators.

The issue came to limelight on Sept. 18 when the Jefferson County Board of Education had proposed establishing a committee to make sure that the courses "promote citizenship, patriotism, essentials and benefits of the free-market system, respect for authority and respect for individual rights" and do not "encourage or condone civil disorder, social strife or disregard of the law," Fox News reported.

Public school curricula are increasingly becoming a point of contention between political conservatives and liberals in the United States. Issues such as evolution, climate change and American history have been particularly contentious. The Texas State Board Of Education controversially adopted a social studies curriculum in 2010, which emphasized the Christian influences of the nation’s founding fathers, and highlighted conservative groups and personalities while downplaying liberal ones.