Evolution's defenders, working to defeat Kansas Board of Education members who oppose modern Darwinian theory, are challenging three incumbent Republican conservatives and the political heir to a fourth in Tuesday's primary.

Impassioned players far removed from what is expected to be a sweltering midsummer primary day are watching the issue. The board's critical stance toward evolution prompted favorable comments from President Bush last year and scorn from the scientific community.

The editor of Scientific American, John Rennie -- who has described the board's conservatives as "six dimwits" -- posted on a blog to urge Kansas voters to defeat board members "who have inflicted embarrassing creationist nonsense on your home's science curriculum standards."