DOVER, Pa., Sept. 23 - Sheree Hied, a mother of five who believes that God created the earth and its creatures, was grateful when her school board here voted last year to require high school biology classes to hear about "alternatives" to evolution, including the theory known as intelligent design.
But 11 other parents in Dover were outraged enough to sue the school board and the district, contending that intelligent design - the idea that living organisms are so inexplicably complex, the best explanation is that a higher being designed them - is a Trojan horse for religion in the public schools.
With the new political empowerment of religious conservatives, challenges to evolution are popping up with greater frequency in schools, courts and legislatures. But the Dover case, which begins Monday in Federal District Court in Harrisburg, is the first direct challenge to a school district that has tried to mandate the teaching of intelligent design.
What happens here could influence communities across the country that are considering whether to teach intelligent design in the public schools, and the case, regardless of the verdict, could end up before the Supreme Court.
Dover, a rural, mostly blue-collar community of 22,000 that is 20 miles south of Harrisburg, had school board members willing to go to the mat over issue. But people here are well aware that they are only the excuse for a much larger showdown in the culture wars.
"It was just our school board making one small decision," Mrs. Hied said, "but it was just received with such an uproar."
For Mrs. Hied, a meter reader, and her husband, Michael, an office manager for a local bus and transport company, the Dover school board's argument - that teaching intelligent design is a free-speech issue - has a strong appeal.
"I think we as Americans, regardless of our beliefs, should be able to freely access information, because people fought and died for our freedoms," Mrs. Hied said over a family dinner last week at their home, where the front door is decorated with a small bell and a plaque proclaiming, "Let Freedom Ring."
But in a split-level house on the other side of Main Street, at a desk flanked by his university diplomas, Steven Stough was on the Internet late the other night, keeping track of every legal maneuver in the case. Mr. Stough, who teaches life science to seventh graders in a nearby district, is one of the 11 parents suing the Dover district. For him the notion of teaching "alternatives" to evolution is a hoax.
"You can dress up intelligent design and make it look like science, but it just doesn't pass muster," said Mr. Stough, a Republican whose idea of a fun family vacation is visiting fossil beds and natural history museums. "In science class, you don't say to the students, 'Is there gravity, or do you think we have rubber bands on our feet?' "
Evolution finds that life evolved over billions of years through the processes of mutation and natural selection, without the need for supernatural interventions. It is the foundation of biological science, with no credible challenges within the scientific community. Without it, the plaintiffs say, students could never make sense of topics as varied as AIDS and extinction.
Advocates on both sides of the issue have lined up behind the case, often calling it Scopes II, in reference to the 1925 Scopes Monkey Trial that was the last century's great face-off over evolution.
On the evolutionists' side is a legal team put together by the American Civil Liberties Union and Americans United for Separation of Church and State. These groups want to put intelligent design itself on trial and discredit it so thoroughly that no other school board would dare authorize teaching it.
Witold J. Walczak, legal director of the A.C.L.U. of Pennsylvania, said the plaintiffs would call six experts in history, theology, philosophy of science and science to show that no matter the perspective, "intelligent design is not science because it does not meet the ground rules of science, is not based on natural explanations, is not testable."
On the intelligent design side is the Thomas More Law Center, a nonprofit Christian law firm that says its mission is "to be the sword and shield for people of faith" in cases on abortion, school prayer and the Ten Commandments. The center was founded by Thomas Monaghan, the Domino's Pizza founder, a conservative Roman Catholic who also founded Ave Maria University and the Ave Maria School of Law; and by Richard Thompson, a former Michigan prosecutor who tried Dr. Jack Kevorkian for performing assisted suicides.
"This is an attempt by the A.C.L.U. to really intimidate this small-town school board," said Mr. Thompson, who will defend the Dover board at the trial, "because the theory of intelligent design is starting to gain some resonance among school boards across the country."
The defense plans to introduce leading design theorists like Michael J. Behe, a professor of biochemistry at Lehigh University, and education experts who will testify that "allowing students to be aware of the controversy is good pedagogy because it develops critical thinking," Mr. Thompson said.
The case, Kitzmiller et al v. Dover Area School District, will be decided by Judge John E. Jones III of the United States District Court, who was nominated by President Bush in 2002 and confirmed by a Senate vote of 96 to 0. The trial is expected to last six weeks and to draw news coverage from around the world.
The legal battle came to a head on Oct. 18 last year when the Dover school board voted 6 to 3 to require ninth-grade biology students to listen to a brief statement saying that there was a controversy over evolution, that intelligent design is a competing theory and that if they wanted to learn more the school library had the textbook "Of Pandas and People: the Central Question of Biological Origins." The book is published by an intelligent design advocacy group, the Foundation for Thought and Ethics, based in Texas.
Angry parents like Mr. Stough, Tammy Kitzmiller, and Bryan and Christy Rehm contacted the A.C.L.U. and Americans United. The 11 plaintiffs are a diverse group, unacquainted before the case, who say that parents, and not the school, should be in charge of their children's religious education.
Mr. Rehm, a father of five and a science teacher who formerly taught in Dover, said the school board had long been pressing science teachers to alter their evolution curriculum, even requiring teachers to watch a videotape about "gaps in evolution theory" during an in-service training day in the spring of 2004.
School board members were told by their lawyer, Mr. Thompson, not to talk to the news media. "We've told them, anything they say can be used against them," Mr. Thompson said.
The Supreme Court ruled in 1987 that teaching creation science in public schools was unconstitutional because it was based on religion. So the plaintiffs will try to prove that intelligent design is creationism in a new package. Richard Katskee, assistant legal director of Americans United, said the "Pandas" textbook only substituted references to "creationism" with "intelligent design" in more recent editions.
Mr. Thompson said his side would prove that intelligent design was not creationism because it did not mention God or the Bible and never posited the creator's identity.
"It's clear they are two different theories," Mr. Thompson said. "Creationism normally starts with the Holy Scripture, the Book of Genesis, then you develop a scientific theory that supports it, while intelligent design looks at the same kind of empirical data that any scientist looks at," and concludes that complex mechanisms in nature "appear designed because it is designed."
A twist in the case is that a leading proponent of intelligent design, the Discovery Institute, based in Seattle, removed one of its staff members from the Dover school board's witness list and opposed the board's action from the start.
"We thought it was a bad idea because we oppose any effort to require students to learn about intelligent design because we feel that it politicizes what should be a scientific debate," said John G. West, a senior fellow at the institute. However, Professor Behe, a fellow at the institute, is expected to be the board's star witness.
Parents in Dover appear to be evenly split on the issue. School board runoffs are in November, with seven candidates opposing the current policy facing seven incumbents. Among the candidates is Mr. Rehm, the former Dover science teacher and a plaintiff. He said opponents had slammed doors in his face when he campaigned and performed a "monkey dance" when he passed out literature at the recent firemen's fair.
But he agrees with parents on the other side that the fuss over evolution has obscured more pressing educational issues like school financing, low parent involvement and classes that still train students for factory jobs as local plants are closing.
"There's no way to have a winner here," Mr. Rehm said. "The community has already lost, period, by becoming so divided."