SAN ANTONIO – Pop quiz: Does the school curriculum adopted in Texas really wind up in textbooks nationwide? If you answered yes, you might get a failing grade.

As the second-largest purchaser of textbooks behind California, the Lone Star State has historically wielded enormous clout in deciding what material appears in classrooms across the country. That’s why the state school board’s recent decision to adopt new social studies standards was closely watched far beyond Texas.

Critics feared the new, more conservative curriculum in Texas would spread elsewhere. But publishing experts say those concerns are overblown.

“It’s easier nowadays to create one edition for one situation and a different edition for another situation,” said Bob Resnick, founder of Education Market Research, based in New York. “I don’t believe the Texas curriculum will spread anyplace else.”

The Texas Board of Education last week approved placing greater emphasis on the Judeo-Christian influences of the nation’s Founding Fathers and teaching schoolchildren that the words “separation of church and state” do not appear in the Constitution.

In Washington, Education Secretary Arne Duncan called the process a case of politicians deciding curriculum. California lawmakers went a step further, proposing that education officials there comb through textbooks to ensure that Texas material isn’t twisting the history curriculum.

This year, as states weigh which textbooks to buy, many “are going to be asking whether this was the book that went to Texas,” said Kathy Mickey, an analyst at Simba Information, a market research firm.

The influence of Texas on the $7 billion U.S. textbook market has steadily weakened.

Technology has made it easier for publishers to tailor textbooks to different standards. That’s especially true in the 20 other states like Texas, where education boards approve textbooks for statewide use.

Substitutions are an easy fix. And publishers won’t gamble on incorporating one state’s controversial curriculum into a one-size-fits-all product for other markets, said Jay Diskey, executive director of the schools division of the Association of American Publishers.

Diskey’s group is the trade group for Houghton Mifflin Harcourt, McGraw-Hill and Pearson Education Inc., which together publish more than 75 percent of the nation’s K-12 textbooks.

“Why would we walk in with stuff that we know might be rejected and knock us out of a business opportunity?” Diskey said.

Even Idaho, which has just 279,000 students in public schools, can sometimes command changes from publishers as easily as Texas does for its 4.8 million schoolchildren.

“Some publishers have added content to their textbooks or other material to make sure they meet Idaho standards,” said Melissa McGrath, spokeswoman for Idaho’s Department of Education.

As for Texas schools, local districts can choose textbooks that the state board deems “nonconforming,” but those books must still contain at least 50 percent of the adopted curriculum.