Brennan Linsley, Associated Press
High school students Bronwyn Elisha, center left, and Tori Leu, center right, cheer as a passing motorist honk in support of their protest against a Jefferson County School Board proposal to emphasize patriotism and downplay civil unrest in the teaching of U.S. history, at Ralston Valley High School, in Arvada, Colo., Tuesday, Sept. 23, 2014. Students from at least two high schools walked out of class Tuesday in the second straight day of protests in Jefferson County.

DENVER — Students and teachers fighting a plan to promote patriotism and downplay civil disobedience in some suburban Denver U.S. history courses are expected to pack a school board meeting Thursday where the controversial changes could face a vote.

Turnout is expected to be so high that the teachers union plans to stream video from the meeting room — which holds a couple hundred people — on a big screen in the parking lot outside. Students were making plans to protest with teachers before the school board meeting but weren't walking out Thursday morning.

Students across a majority of the 17 high schools in Colorado's second-largest school district have left classes in droves over the past few weeks, waving signs and flags in protests organized by word of mouth and social media.

The protests started Sept. 19, when the Jefferson County school board proposed creating a committee to review texts and course plans, starting with Advanced Placement history, to make sure materials "promote citizenship, patriotism, essentials and benefits of the free-market system, respect for authority and respect for individual rights" and don't "encourage or condone civil disorder, social strife or disregard of the law."

Teachers upset about the history proposal as well as a merit-based compensation package they consider unfair started staging sick-ins, where they call out sick and force school to be canceled some days.

On Wednesday, eight organizations, including the National Coalition Against Censorship and the American Civil Liberties Union of Colorado, sent a letter to the board saying, "Decisions about instructional materials should be based on sound educational grounds, not because some people do or do not agree with the message."

The board's majority is a conservative bloc of three new members elected last year. They instantly became the majority, pushing out the district's veteran superintendent and clashing with its teachers union and parent-teacher association.

There's no sign conservatives want to back off creating a review committee, although the latest proposal omits some of the more controversial language. Superintendent Dan McMinimee has said he will ask the board to appoint students to the committee.

Those changes likely won't satisfy hundreds of students who have been leaving class to protest in waves for over a week. The history class was just the first of the Advanced Placement classes to be reviewed.

Ashlyn Maher, 18, a Chatfield High School senior who has been helping organize protests, said she doesn't want the board to move on next to reviewing curriculum of other classes, such as AP literature, and deciding which books students can read.

"We are not going to settle for empty promises. We want the school board to listen and take action on what we've said," she said.

Board member Julie Williams, who originally proposed that the committee review materials for classes, and other backers of the proposal say students are being used as pawns by teachers upset about the plan to base raises on an evaluation system.

There had been talk of students trying to prove a point by walking out of class Wednesday, the day school districts across the state are required to take a student head count to determine how much funding they will get. However, districts can take additional steps to prove students were in class on other days, and student organizers say they didn't want to create needless work for district officials.