A leading conservative on Texas' Board of Education floated the idea of walking out of an upcoming discussion on a controversial Mexican-American studies textbook to "deny the Hispanics a record vote," according to an email a watchdog group released Wednesday.

The board is set to vote in November on a high-school level Mexican-American studies book. The debate follows years of ideological clashes over teaching such topics as evolution, climate change and Christianity's influence on America's Founding Fathers for the more than 5.2 million public school students statewide.

The book stands little chance of winning approval. Democrats, scholars and advocacy groups call it inaccurate and offensive. Some Republican board members have questioned the necessity of a specialized book on the subject.

The left-leaning Texas Freedom Network used an open records request to obtain an email in which David Bradley, a Republican from Beaumont, suggests skipping the vote to a Republican colleague. If enough board members boycott the proceedings, the book would be defeated without a recorded vote.

Reached by phone Wednesday, Bradley declined to say if 'the Hispanics' referred specifically to other board members or activists who have for weeks pressured the board to defeat the book.

"There was a certain level of frustration with the volume and the intensity of the political campaign that Mr. Cortez was running," Bradley said, referring to Ruben Cortez, a Democratic board member from Brownsville who has been one of the proposed book's most-outspoken critics.

Bradley added that he wanted to spare the board negative attention, saying: "Our attempt was to try and shut down a CNN moment." He said that, despite the email, he does plan to attend the book vote.

Texas Freedom Network spokesman Dan Quinn said the email shows that "the tone of the debate has gotten as sickening as the textbook is."

Democrats, who are outnumbered 10-5 on the education board, pushed unsuccessfully to create a full Mexican-American studies program in high schools. Instead, publishers were asked to submit textbooks on a variety of ethnic studies topics that the board could consider for use beginning in the 2017-2018 academic year.

Texas got just one submission. Virginia-based publisher Momentum Instruction offered a textbook titled "Mexican American Heritage."

Critics decry the book's suggesting that Mexican culture promotes laziness, linking Mexican-Americans to immigrants in the country legally, and characterizing leaders of the Chicano movement that advanced Mexican-American civil rights in the 1960s and 1970s as adopting "a revolutionary narrative that opposed Western civilization and wanted to destroy this society."

"Mexican laborers were not reared to put in a full day's work," the textbook states, according to excerpts. "There was a cultural attitude of 'manana,' or 'tomorrow.'"

Hispanics make up 52 percent of Texas public school students, with most being Mexican-Americans.

Texas' more than 1,000 school districts don't have to use board-sanctioned classroom materials, but most do. Texas' market is therefore so large that edits made by publishers to meet the state's curriculum standards can wind up altering content in textbooks sold elsewhere.