The battle for the hearts and minds of American school children took another turn this week. The infamous Kansas school board that voted to banish Darwin from the science curriculum has welcomed him back with open arms, spurning instead the language of intelligent design.

The school board has voted, 6-4, to remove the language of intelligent design from the curriculum: science teachers will no longer have to say that the central ideas of evolution are controversial in scientific circles.

The explanation of the "nature of science" has also been reworded. It is now described as the pursuit of rational explanations for things that happen in the Universe.

"Today the Kansas Board of Education returned its curriculum standards to mainstream science," said board chairman, Dr Bill Wagnon. "This assures that Kansas children are appropriately educated for the 21st century."

But while the change should be seen as significant, it is the fourth shift in policy in Kansas in the last eight years, and is unlikely to be the last. The ID camp is very well organized: a day after the new standards were announced, the Intelligent Design Network presented the school board with a petition protesting the changes. It contained the signatures of almost 4,000 parents.

For anyone new to this long-running debate, here's a re-cap.

In 1987 the supreme court in the US ruled that teaching creationism in science classes was unconstitutional. Since then, creationists have given their backing to an idea called intelligent design (ID). This takes God out of the equation, at least explicitly. Instead of insisting on a six-days-to-make-the-world story, it argues that life is too complex to have evolved without the input of some intelligent designer.

The implication is that this designer is God, although there are those who would argue that it could be very clever aliens, too. We'll not dwell on that, except to direct your attention to the web page of a man called Rael, and his "Raelien" followers. Drawing conclusions is left as an exercise for the reader.

The proponents of the ID "theory" have argued very strongly, and with some successes, that ID should be taught as a counter to the theory of evolution in science classes. The most notable win for the ID camp was in Kansas, while Pennsylvania has been the scene of a hard won victory for the scientists.

California, Georgia, Kentucky, Louisiana, Ohio, Nevada, and South Carolina have all also seen either high profile debates or legal wrangling over evolution's place in schools.

School board member Sue Gamble said the changes were important for Kansas if it was "to have an educated populace". But ID supporters say the changes undermine families who reject the morality of materialism.

The new guidelines in Kansas supersede the old ones with immediate effect, and the poor school kids of Kansas will have to adjust to a new set of rules ahead of tests in the next school year. You can read the old and new science standards here.

Opponents are accusing the Board of promoting atheism. 4000 Kansas residents signed their name to a petition opposing the new standards.